Allow motion's %$ conversion specifier

[MichaIng]

This commit was done with an anonymous account in context of a study. The actual author might want to open a PR with its true account for proper credits, after the study ended. However, I am opening this here to show that this issue has been addressed, so no one starts doubled work 😉.

My only concern was that it re-introduced this RCE vulnerability: GHSA-j945-qm58-4gjx
However, the %$ seems to be replaced by motion before it is piped through the shell, so %$VARIALE and %$(command) are expanded to Camera1VARIABLE and Camera1(command) respectively, no variable or command substitution hence happens.

[MichaIng]

@copilot
A translated string is expanded a way here, which does not require human re-translation. Please replace the respective origin string in the backend's .po files, and add the %$ to the translations as well. So msgmerge (and Weblate) won't treat this as new string, but keep the old translation just with %$ added.

[Copilot]

@MichaIng I've opened a new pull request, #3274, to work on those changes. Once the pull request is ready, I'll request review from you.

[MichaIng]

Great #3274 is ready to be merged into whichever PR adds this change. That way we avoid any additional translation needs. A blueprint for whenever we change source strings in a sufficiently trivial way, or in a way which does not render the translations entirely wrong. If some native speaker shall better have a look, we can let Copilot add the fuzzy tag, maybe even another custom tag: so it appears as unfinished in Weblate, but without the existing translation lost, and optionally with some custom explanation.