[Chapel Merge] Fix `PascalCaseClasses` for single letters

Branch: refs/heads/main
Revision: ca16ef7cbd5832519db47bcfc671f94325d7c267
Author: jabraham17
Link: Fix `PascalCaseClasses` for single letters by jabraham17 · Pull Request #23949 · chapel-lang/chapel · GitHub
Log Message:
Fix PascalCaseClasses for single letters (#23949)

Fixes rule for pascal case in chplcheck to allow single letters in
pascal case. For example, class AClass was getting flagged as not
being pascal case. This is now fixed.

while there, added a future for a bug with UnusedFormal

[Reviewed by @brandon-neth]

Compare: Comparing d99457c50023ffbe3785cf1019640230b8359e05...93b956907772dc059615e1f7e6aceda63391326a · chapel-lang/chapel · GitHub

M test/chplcheck/CaseRules.chpl
M test/chplcheck/CaseRules.good
M test/chplcheck/PREDIFF
A test/chplcheck/UnusedFormalBug.bad
A test/chplcheck/UnusedFormalBug.chpl
A test/chplcheck/UnusedFormalBug.future
A test/chplcheck/UnusedFormalBug.good
M tools/chplcheck/src/rules.py