Fix Validation Script to Not Error Out if Bullet Points Don't End with Period

[WillAyd]

Quite a few PRs lately have worked around the validation script error of descriptions not ending with a period when there are bullet points by adding periods to the end of each bullet point. This looks tacky and is really just a hack to get around the validator failing.

Would rather update the validator to maybe ignore bullet points as part of the description, though @datapythonista may have other thoughts.

xref #20298

[gwrome]

This could be as simple as removing two lines from the validator:

if doc.parameter_desc(param)[-1] != '.':
  errs.append(error('PR09', param_name=param))

This solution is effectively the same as removing error code PR09.

Is this the outcome you're looking for? Or are there cases in which you want the validator to complain about bullets not ending in periods?