File / Save Incremental Operator

This is just an addition to the File Menu for "Save Incremental" that immediately saves the current file with a numerically-incremented file name. So if "example.blend" it will save as "example1.blend", "test0099.blend" will save as "test0100.blend", etc. So the same as if you selected File / Save As, then clicked "+" until you found the first available filename. The poll function will leave it disabled if the current file has never been saved.

This is an implementation of a Right-Click Select request with 63 votes

I find the name "Save Incremental" slightly odd, because of my background in network administration where an incremental save is saving just the changes. But this name seems normal within our competitor programs, so I think it will make sense to users.

It does make the File Menu longer of course. But that might mean it is a nice time to reorganize it, like in D8706: UI - Topbar Menu Changes