i18n: remove source code references from kallithea.po files Remove all comments with source code references from the kallithea.po files. Such meta data will inherently be outdated, and create unnecessary churn and repository growth, making it harder to spot actual and important changes. None of the removed information is actually 'lost', it can be regenerated via extract_messages/msgmerge, see instructions in kallithea/i18n/how_to. This commit is part of a series that normalizes the kallithea.po files by removing all comments, in particular source code references.