Check translator comments with clang-tidy

[Qrox]

Summary

SUMMARY: Build "Check translator comments with clang-tidy"

Purpose of change

Translator comments need to be preceding the extracted string and on the same or adjacent line to be properly recognized by xgettext. However, sometimes the translation calls need to be split into multiple lines due to styling, and newly added code can also unintentionally separate the comments from the extracted string. Because this kind of errors are not always obvious, this PR adds a clang-tidy check to check translator comments that does not have a matching string.

Describe the solution

Translator comments and macros are first recorded. AST matchers are then used to match strings in translation function calls and macros. Comments correctly preceding the found strings are then marked. After all strings are processed, unmarked comments are considered to be misplaced, and reported as errors.

Describe alternatives you've considered

A regex solution would be complicated and hard to maintain, due to the fact that a translator comment can be positioned after the translation function and before the extracted string.