Fix regression in autodoc.Documenter.parse_name (#11613)

If the assert statement added in GH-11523 fails,
the build fails and the user only sees
``assert matched is not None``.
With this change, the user gets a proper warning message
containing the name of the offending module,
and the build will succeed.

Signed-off-by: Zack Cerza <zack@redhat.com>
Co-authored-by: Zack Cerza <zack@redhat.com>
Co-authored-by: Adam Turner <9087854+aa-turner@users.noreply.github.com>

CHANGES

@@ -4,6 +4,7 @@ Release 7.2.3 (in development)
 Bugs fixed
 ----------
 
+* Fix regression in ``autodoc.Documenter.parse_name()``.
 
 Release 7.2.2 (released Aug 17, 2023)
 =====================================

sphinx/ext/autodoc/__init__.py

@@ -383,14 +383,12 @@ def parse_name(self) -> bool:
         # first, parse the definition -- auto directives for classes and
         # functions can contain a signature which is then used instead of
         # an autogenerated one
-        try:
-            matched = py_ext_sig_re.match(self.name)
-            assert matched is not None
-            explicit_modname, path, base, tp_list, args, retann = matched.groups()
-        except AttributeError:
+        matched = py_ext_sig_re.match(self.name)
+        if matched is None:
             logger.warning(__('invalid signature for auto%s (%r)') % (self.objtype, self.name),
                            type='autodoc')
             return False
+        explicit_modname, path, base, tp_list, args, retann = matched.groups()
 
         # support explicit module and class name separation via ::
         if explicit_modname is not None: