Add pyreadline3 backup import for readline (#1332)

* Add pyreadline3 backup import for readline

`readline` is unavailable on Windows. Without this fix, the following error occurs when attempting to launch yewtube:

```
  File "C:\Python313\Lib\site-packages\mps_youtube\commands\__init__.py", line 28, in command
    completer.add_cmd(command)
    ^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'add_cmd'```

* Fix readline import handling in main.py

Handle ImportError for pyreadline3 and set has_readline flag.

---------

Co-authored-by: Talha Asghar <[email protected]>

Author: JodanJodan

mps_youtube/main.py

@@ -29,18 +29,23 @@
 from . import util
 
 completer = None
+readline = None
 try:
     import readline
+except ImportError:
+    try:
+        from pyreadline3 import Readline
+        readline = Readline()
+    except ImportError:
+        has_readline = False
+if readline:
     readline.set_history_length(2000)
     has_readline = True
     completer = util.CommandCompleter()
     readline.parse_and_bind('tab: complete')
     readline.set_completer(completer.complete_command)
     readline.set_completer_delims('')
 
-except ImportError:
-    has_readline = False
-
 from . import g, c, commands, screen, history, init
 from . import __version__, playlists, content, listview
 from . import config