refactor: clean up keybinding implementations

- Cleans and organizes key binding definitions for plugins and user
keybinds.

- Update documentation for keybindings

conf.d/fish_frozen_key_bindings.fish

@@ -1,14 +0,0 @@
-# This file was created by fish when upgrading to version 4.3, to migrate
-# the 'fish_key_bindings' variable from its old default scope (universal)
-# to its new default scope (global).  We recommend you delete this file
-# and configure key bindings in ~/.config/fish/config.fish if needed.
-
-# set --global fish_key_bindings fish_default_key_bindings
-
-# Prior to version 4.3, fish shipped an event handler that runs
-# `set --universal fish_key_bindings fish_default_key_bindings`
-# whenever the fish_key_bindings variable is erased.
-# This means that as long as any fish < 4.3 is still running on this system,
-# we cannot complete the migration.
-# As a workaround, erase the universal variable at every shell startup.
-set --erase --universal fish_key_bindings

conf.d/keybindings.fish

@@ -1,11 +0,0 @@
-# Copyright (C) 2026 Rootiest
-# SPDX-License-Identifier: AGPL-3.0-or-later
-
-if not status is-interactive
-    exit
-end
-
-# Ctrl+Alt+U — strip the first command token and place cursor at start to retype it
-for mode in default insert
-    bind --mode $mode ctrl-alt-u _replace_command_token
-end