fix docstring typo in bdb.py (GH-22323) (#26180)

(cherry picked from commit be54fb5)

Co-authored-by: flizzywine <[email protected]>

Author: miss-islington

Lib/bdb.py

@@ -117,7 +117,7 @@ def dispatch_call(self, frame, arg):
         """Invoke user function and return trace function for call event.
 
         If the debugger stops on this function call, invoke
-        self.user_call(). Raise BbdQuit if self.quitting is set.
+        self.user_call(). Raise BdbQuit if self.quitting is set.
         Return self.trace_dispatch to continue tracing in this scope.
         """
         # XXX 'arg' is no longer used