Rename Trackversions via PLE

That already exists in the ‘rename Track Version’ command, which pops up a dialog.
I’ve made a meta grid function that pops in names there, but it’s clunky - not something I’d like to be fiddling with during a recording session where every minute counts.

PLE renaming already exists for other items, such as tracks and events, so it really seems logical to extend this to track versions.