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/completions/bind.fish

@@ -57,5 +57,21 @@ complete -c bind -s s -l silent -d 'Operate silently'
 complete -c bind -l preset -d 'Operate on preset bindings'
 complete -c bind -l user -d 'Operate on user bindings'
 
-complete -c bind -n __fish_bind_test1 -a '(bind --key-names)' -d 'Key name' -x
 complete -c bind -n __fish_bind_test2 -a '(bind --function-names)' -d 'Function name' -x
+
+function __fish_bind_complete
+    argparse M/mode= m/sets-mode= preset user s/silent \
+        a/all function-names list-modes e/erase -- (commandline -xpc)[2..] 2>/dev/null
+    or return 1
+    set -l token (commandline -ct)
+    if test (count $argv) = 0 && set -l prefix (string match -r -- '(.*,)?(ctrl-|alt-|shift-)*' $token)
+        printf '%sctrl-\tCtrl modifier…\n' $prefix
+        printf '%salt-\tAlt modifier…\n' $prefix
+        printf '%sshift-\tShift modifier…\n' $prefix
+        set -l key_names plus minus comma backspace delete escape \
+            enter up down left right pageup pagedown home end insert tab \
+            space F(seq 12)
+        printf '%s\tNamed key\n' $prefix$key_names
+    end
+end
+complete -c bind -k -a '(__fish_bind_complete)' -f