Most work was done in 7dc0a05a71, though `check_translation.rb` still had a hardcoded shebang. This is now fixed. #2590 is now fully resolved too.
7dc0a05a71
[Helper] Redis timeout set to 0 in NC [Helper] Small fixes to check_translations script
helper-scripts/check_translations.rb checks if keys present in the master translation file are used in any php or js code. Writes a sed comand to stdout to remove unused keys from all lang files. This saves unnecessary work when translating.
