Re-word comment on unreachable return statements

Do not use the word "warning" in the comment because CTest launchers
match it and CTestCustom.cmake.in does not suppress it.
Merge topic 'suppress-warning-in-comment' into next

621c2bc0 Re-word comment on unreachable return statements
Re-word comment on unreachable return statements

Do not use the word "warning" in the comment because CTest launchers
match it and CTestCustom.cmake.in does not suppress it.
Merge topic 'suppress-warning-in-comment' into next

72e137ea Re-word comment on unreachable return statements