docs: fixed variable name in ASGIMiddleware code example (#4151)

docs: fixed variable name in ASGIMiddleware code example (#4149)

Author: mmev

litestar/middleware/base.py

@@ -194,7 +194,7 @@ class MyMiddleware(ASGIMiddleware):
             exclude_opt_key = "exclude_my_middleware"
 
             def __init__(self, my_logger: Logger) -> None:
-                self.logger = logger
+                self.logger = my_logger
 
             async def handle(
                 self, scope: Scope, receive: Receive, send: Send, next_app: ASGIApp