[Chapel Merge] docs(generics): add test for MemberWidth example

Branch: refs/heads/main
Revision: a5d4cf00ac813be8e77203bcdd76aea7bddff940
Author: arezaii
Link: docs(generics): add test for MemberWidth example by arezaii · Pull Request #21923 · chapel-lang/chapel · GitHub
Log Message:
docs(generics): add test for MemberWidth example (#21923)

This PR fixes failing spectests that started after
docs(generics): update parameters with user submitted example by arezaii · Pull Request #21902 · chapel-lang/chapel · GitHub. This commit was
supposed to be part of that PR, but didn't get pushed prior to it being
merged due to user error (It was ME!)

The test was missing the command-line execopts and known good output to
compare.

TESTING:

  • make spectests and test MemberWidth.chpl

reviewed by @mppf

Compare: Comparing 2ca475311161ca663f251813aec8a28ff97f93d6...d84f3a54989cb4c24c938295d1e58ac7072e1ae5 · chapel-lang/chapel · GitHub

Diff:
M doc/rst/language/spec/generics.rst
https://github.com/chapel-lang/chapel/pull/21923.diff