Backport: Fix comment-empty-lines docstring (bug#35152)
* lisp/newcomment.el (comment-empty-lines): Consistently use US commas in docstring. Fix indentation of and typo in custom :type. (cherry picked from commit 690c678f)
* lisp/newcomment.el (comment-empty-lines): Consistently use US commas in docstring. Fix indentation of and typo in custom :type. (cherry picked from commit 690c678f)