[LyX/master] use std::move() instead of copying when value is no longer used

[Jürgen Spitzmüller]

Am Samstag, dem 07.09.2024 um 13:22 +0200 schrieb Jean-Marc Lasgouttes:
> I have been resisting to making these changes because someone may
> change the code and use the variable afterwards. But I may be wrong
> after all.

I am not sure at all. I did some research how useful this sort of
advise is, and people seem to be ambivalent about it. So I am perfectly
fine with reverting it and ignoring the message (or let coverity ignore
it).

-- 
Jürgen