DOC, MAINT: remove use of inspect.formatargspec during doc build

[tirthasheshpatel]

Reference issue

Doc build doesn't work on Python 3.11.

Sphinx build log with Python 3.11

fatal: bad revision '^v1.8.0'
fatal: bad revision '^v1.8.0'
fatal: bad revision '^v1.8.0'
# for testing
# @echo installed scipy 48c3dc8 matches git version 48c3dc8; exit 1
mkdir -p build/html build/doctrees
LANG=C python3 -msphinx -WT --keep-going  -b html -d build/doctrees -j12 source build/html 
Running Sphinx v5.3.0
SciPy (VERSION 1.10.0.dev0+0.48c3dc8)
/home/tirthasheshpatel/oss/virtualenvs/scipy-dev/lib/python3.11/site-packages/sphinx/util/images.py:4: DeprecationWarning: 'imghdr' is deprecated and slated for removal in Python 3.13
  import imghdr
[autosummary] generating autosummary for: dev/api-dev/api-dev-toc.rst, dev/api-dev/nan_policy.rst, dev/api-dev/special_ufuncs.rst, dev/conduct/code_of_conduct.rst, dev/conduct/report_handling_manual.rst, dev/contributor/adding_new.rst, dev/contributor/benchmarking.rst, dev/contributor/building.rst, dev/contributor/building_faq.rst, dev/contributor/compiled_code.rst, ..., tutorial/stats/discrete_zipf.rst, tutorial/stats/discrete_zipfian.rst, tutorial/stats/resampling.rst, tutorial/stats/sampling.rst, tutorial/stats/sampling_dau.rst, tutorial/stats/sampling_dgt.rst, tutorial/stats/sampling_hinv.rst, tutorial/stats/sampling_pinv.rst, tutorial/stats/sampling_srou.rst, tutorial/stats/sampling_tdr.rst
[autosummary] generating autosummary for: /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/czt-function.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/odr-function.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.LowLevelCallable.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.cluster.hierarchy.ClusterNode.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.cluster.hierarchy.DisjointSet.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.cluster.hierarchy.average.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.cluster.hierarchy.centroid.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.cluster.hierarchy.complete.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.cluster.hierarchy.cophenet.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.cluster.hierarchy.correspond.rst, ..., /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.wrapcauchy.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.yeojohnson.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.yeojohnson_llf.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.yeojohnson_normmax.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.yeojohnson_normplot.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.yulesimon.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.zipf.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.zipfian.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.zmap.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.zscore.rst
[autosummary] generating autosummary for: /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.LowLevelCallable.__getitem__.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.LowLevelCallable.__len__.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.LowLevelCallable.__mul__.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.LowLevelCallable.count.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.LowLevelCallable.from_cython.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.LowLevelCallable.function.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.LowLevelCallable.index.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.LowLevelCallable.signature.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.LowLevelCallable.user_data.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.cluster.hierarchy.ClusterNode.get_count.rst, ..., /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.sampling.NumericalInversePolynomial.set_random_state.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.sampling.NumericalInversePolynomial.u_error.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.sampling.SimpleRatioUniforms.rvs.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.sampling.SimpleRatioUniforms.set_random_state.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.sampling.TransformedDensityRejection.hat_area.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.sampling.TransformedDensityRejection.ppf_hat.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.sampling.TransformedDensityRejection.rvs.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.sampling.TransformedDensityRejection.set_random_state.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.sampling.TransformedDensityRejection.squeeze_area.rst, /home/tirthasheshpatel/oss/scipy/doc/source/reference/generated/scipy.stats.sampling.TransformedDensityRejection.squeeze_hat_ratio.rst
loading intersphinx inventory from https://docs.python.org/3/objects.inv...
loading intersphinx inventory from https://numpy.org/devdocs/objects.inv...
loading intersphinx inventory from https://numpy.org/neps/objects.inv...
loading intersphinx inventory from https://matplotlib.org/stable/objects.inv...
loading intersphinx inventory from https://asv.readthedocs.io/en/stable/objects.inv...
building [mo]: targets for 0 po files that are out of date
building [html]: targets for 328 source files that are out of date
updating environment: [new config] 4317 added, 0 changed, 0 removed
reading sources... [  9%] reference/generated/scipy.interpolate.BivariateSpline.ev .. reference/generated/scipy.interpolate.LSQBivariateSpline.get_coeffs                                                 
Traceback (most recent call last):
  File "/home/tirthasheshpatel/oss/virtualenvs/scipy-dev/lib/python3.11/site-packages/sphinx/cmd/build.py", line 281, in build_main
    app.build(args.force_all, args.filenames)
  File "/home/tirthasheshpatel/oss/virtualenvs/scipy-dev/lib/python3.11/site-packages/sphinx/application.py", line 347, in build
    self.builder.build_update()
  File "/home/tirthasheshpatel/oss/virtualenvs/scipy-dev/lib/python3.11/site-packages/sphinx/builders/__init__.py", line 310, in build_update
    self.build(to_build,
  File "/home/tirthasheshpatel/oss/virtualenvs/scipy-dev/lib/python3.11/site-packages/sphinx/builders/__init__.py", line 326, in build
    updated_docnames = set(self.read())
                           ^^^^^^^^^^^
  File "/home/tirthasheshpatel/oss/virtualenvs/scipy-dev/lib/python3.11/site-packages/sphinx/builders/__init__.py", line 431, in read
    self._read_parallel(docnames, nproc=self.app.parallel)
  File "/home/tirthasheshpatel/oss/virtualenvs/scipy-dev/lib/python3.11/site-packages/sphinx/builders/__init__.py", line 487, in _read_parallel
    tasks.join()
  File "/home/tirthasheshpatel/oss/virtualenvs/scipy-dev/lib/python3.11/site-packages/sphinx/util/parallel.py", line 105, in join
    if not self._join_one():
           ^^^^^^^^^^^^^^^^
  File "/home/tirthasheshpatel/oss/virtualenvs/scipy-dev/lib/python3.11/site-packages/sphinx/util/parallel.py", line 126, in _join_one
    raise SphinxParallelError(*result)
sphinx.errors.SphinxParallelError: AttributeError: module 'inspect' has no attribute 'formatargspec'

Sphinx parallel build error:
AttributeError: module 'inspect' has no attribute 'formatargspec'
make: *** [Makefile:110: html-build] Error 2

real	0m21.865s
user	1m22.244s
sys	0m14.798s

What does this implement/fix?

inspect.formatargspec was deprecated in Python 3.5 and has been removed in Python 3.11. This PR replaces the use of inspect.formatargspec with inspect.signature so that the doc builds succeed on Python 3.11.

Additional information

Once this and executablebooks/sphinx-design#105 merge, doc builds should succeed on Python 3.11

[tupui]

LGTM thanks @tirthasheshpatel