expose a way for registering the command error manager

The manager instance needs to be bound "late" due to the bot since error handlers might need an instance of bot to work

Author: shtlrs

pydis_core/_bot.py

@@ -95,9 +95,11 @@ def __init__(
         super().__init__(
             *args,
             allowed_roles=allowed_roles,
+            tree_cls=CommandTreeBase,
             **kwargs,
         )
 
+        self.command_error_manager: CommandErrorManager | None = None
         self.guild_id = guild_id
         self.http_session = http_session
         self.api_client = api_client
@@ -119,6 +121,16 @@ def __init__(
 
         self.all_extensions: frozenset[str] | None = None
 
+    def register_command_error_manager(self, manager: CommandErrorManager) -> None:
+        """
+        Bind an instance of the command error manager to both the bot and the command tree.
+
+        The reason this doesn't happen in the constructor is because error handlers might need an instance of the bot.
+        So registration needs to happen once the bot instance has been created.
+        """
+        self.command_error_manager = manager
+        self.tree.command_error_manager = manager
+
     def _connect_statsd(
         self,
         statsd_url: str,