Extended & human-friendly keys

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

share/functions/edit_command_buffer.fish

@@ -86,13 +86,10 @@ function edit_command_buffer --description 'Edit the command buffer in an extern
         set -a editor $f
     end
 
-    __fish_disable_bracketed_paste
     $editor
-    set -l editor_status $status
-    __fish_enable_bracketed_paste
 
     # Here we're checking the exit status of the editor.
-    if test $editor_status -eq 0 -a -s $f
+    if test $status -eq 0 -a -s $f
         # Set the command to the output of the edited command and move the cursor to the
         # end of the edited command.
         commandline -r -- (command cat $f)