Remove the last non scoped place where we disable protocols (just before
exec(1)); it's not necessary with the current approach because we always
disable inside eval.
There is an edge case where we don't:
fish -ic "exec bash"
leaving bash with CSI u enabled. Disable that also in -ic mode where we
don't have a reader.
In future we should use the same approach for restore_term_mode() but I'm
not sure which one is better.
See the changelog additions for user-visible changes.
Since we enable/disable terminal protocols whenever we pass terminal ownership,
tests can no longer run in parallel on the same terminal.
For the same reason, readline shortcuts in the gdb REPL will not work anymore.
As a remedy, use gdbserver, or lobby for CSI u support in libreadline.
Add sleep to some tests, otherwise they fall (both in CI and locally).
There are two weird failures on FreeBSD remaining, disable them for now
https://github.com/fish-shell/fish-shell/pull/10359/checks?check_run_id=23330096362
Design and implementation borrows heavily from Kakoune.
In future, we should try to implement more of the kitty progressive
enhancements.
Closes#10359
