Several problematic messages

Just for others to understand the problem: The issue was with these two messages:

• Wikiedudashboard-campaign.data editor usernames info ("List of editor usernames, one per line")
• Wikiedudashboard-campaign.data wikidata info ("Detailed breakdown of Wikidata activity, based on edit summaries")

And most importantly, only for French. The problem was caused by the change to fr.yml in this commit – two new messages were inserted one line too high up, resulting in the original "data_editor_usernames_info" message being split into two at a line break, removing the word "ligne" from one message and adding the same word to an unrelated message.

That's a weird effect of the ".yml" format, which uses continuation lines, instead of explicit delimitation of end of messages.

The source edit was to insert some messages at "random" position, in the middle of another message (between its first line, and the following continuation line.

I wonder if this happens regularly for other "*.yml" localisation files (there are many of them, such edits are probably automated). This should not happen if it used the JSON format (at least the syntax error would be detected early), or if that message (supposed to be interpreted as one line, without any linebreak) was not using the YML continuation syntax to split them above some arbitrary line length (really not needed in localization source files).

The YML format is cool for human edits (file per file), but not for automated edits using basic regexps (e.g. with sed, awk or bash script) which are dangerous across a large set of files when the human will superficially look at the changes (and no syntax error will be detected). For now there were only two locale files "en" and "fr", but soon there will be hundreds generated from translations in TWN.

See https://github.com/WikiEducationFoundation/WikiEduDashboard/issues/4824