feat: show truncated help on some errors

[mdonnalley]

• Show USAGE, FLAGS, and ARGUMENTS on Unexpected argument, Nonexistent flag, and Required arg errors

❯ bin/run.js hello world --DOES_NOT_EXIST
 ›   Error: Nonexistent flag: --DOES_NOT_EXIST
 ›   See more help with --help

USAGE
  $ oex hello world [--flag1 <value>]

FLAGS
  --flag1=<value>

• Adds sections and sendToStderr options to HelpOptions
  • Setting sections allows users to select which help sections they want printed. If undefined, it will show all sections.
  • Setting sendToStderr will send all help output to stderr instead of stdout
• Moves error and warn functions into separate files so we can avoid circular imports

Fixes #679

@W-15103729@

[cristiand391]

tested with plugin-plugins and some changes to make args required:

missing required arg

./bin/run.js plugins inspect, with arg requred=true:

➜  plugin-plugins git:(main) ✗ ./bin/run.js plugins inspect
 ›   Error: Missing 1 required arg:
 ›   plugin  Plugin to inspect.
 ›   See more help with --help

USAGE
  $ mycli plugins inspect PLUGIN...

ARGUMENTS
  PLUGIN  Plugin to inspect.

FLAGS
  -h, --help     Show CLI help.
  -v, --verbose

GLOBAL FLAGS
  --json  Format output as json.

unknown flag

➜  plugin-plugins git:(main) ✗ ./bin/run.js plugins inspect data --asfd
 ›   Error: Nonexistent flag: --asfd
 ›   See more help with --help

USAGE
  $ mycli plugins inspect PLUGIN...

ARGUMENTS
  PLUGIN  Plugin to inspect.

FLAGS
  -h, --help     Show CLI help.
  -v, --verbose

GLOBAL FLAGS
  --json  Format output as json.

unexpected arg:

➜  plugin-plugins git:(main) ✗ ./bin/run.js plugins link test toast
 ›   Error: Unexpected argument: toast
 ›   See more help with --help

USAGE
  $ mycli plugins link PLUGIN

ARGUMENTS
  PATH  [default: .] path to plugin

FLAGS
  -h, --help          Show CLI help.
  -v, --verbose
      --[no-]install  Install dependencies after linking the plugin.

help is sent to stderr:

./bin/run.js plugins inspect 2> stderr.txt

➜  plugin-plugins git:(main) ✗ cat stderr.txt
 ›   Error: Missing 1 required arg:
 ›   plugin  Plugin to inspect.
 ›   See more help with --help

USAGE
  $ mycli plugins inspect PLUGIN...

ARGUMENTS
...