OSC 133 was added to tmux 3.4.
Also fix the test on macOS where we do have 3.5a in CI; for some reason we
get copy_cursor_y=6 there. I didn't investigate yet but at least that's
not the same bug this test was made to fix.
For multi-line prompts, we start each leading line with a clr_eol. Immediately
before printing these prompt lines we emit the OSC 133 prompt start marker.
Some terminals such as tmux interpret make clr_eol delete such markers,
hence prompt navigation is broken.
Fix this by printing the marker only after clr_eol.
The scenario where this triggers is quite odd. I haven't looked into why
the problem doesn't exist if I remove the recursive repaint request.
See https://github.com/tmux/tmux/issues/4183Closes#10776
