A new watcher option for kitty.conf that replaces the old --watcher cli flag

Applies to all windows, not just initial ones.

kitty/cli.py

@@ -571,15 +571,6 @@ def parse_cmdline(oc: Options, disabled: OptionSpecSeq, ans: Any, args: Optional
     return leftover_args
 
 
-WATCHER_DEFINITION = '''
---watcher -w
-type=list
-Path to a python file. Appropriately named functions in this file will be called
-for various events, such as when the window is resized, focused or closed. See the section
-on watchers in the launch command documentation :doc:`launch`. Relative paths are
-resolved relative to the kitty config directory.'''
-
-
 def options_spec() -> str:
     if not hasattr(options_spec, 'ans'):
         OPTIONS = '''
@@ -627,11 +618,6 @@ Path to a file containing the startup :italic:`session` (tabs, windows, layout,
 Use - to read from STDIN. See the README file for details and an example.
 
 
-{watcher}
-Note that this watcher will be added only to all initially created windows, not new windows
-created after startup.
-
-
 --hold
 type=bool-set
 Remain open after child process exits. Note that this only affects the first
@@ -731,7 +717,6 @@ type=bool-set
 '''
         setattr(options_spec, 'ans', OPTIONS.format(
             appname=appname, config_help=CONFIG_HELP.format(appname=appname, conf_name=appname),
-            watcher=WATCHER_DEFINITION
         ))
     ans: str = getattr(options_spec, 'ans')
     return ans