expand + undo leaves buffer modified

[sam-s]

Visit, say, python buffer, save it, and type p TAB C-/ (print snippet expand and immediately undo).
The buffer is now back to its saved state but it is marked as modified in the mode line.

yasnippet (version 20241013.1557) -- pluskid/joaotavora/npostavs

[monnier]

Visit, say, python buffer, save it, and type `p TAB C-/` (`print` snippet expand and immediately `undo`).

Hmm... I can't reproduce it: - `p TAB` doesn't do anything. So I used `prop TAB` instead. - `C-/` undoes only the expansion, but a subsequent `C-/` undoes the insertion of `prop` and sets the buffer as unmodified as it should. - I tried `prop C-x C-s TAB C-/` and the buffer was also properly marked as unmodified. That was using the `yasnippet-classic-snippets` and `yasnippet` from Git.