Adds missing urllib.parse for IDE warning of PubMedAPIWrapper (#12808)

Resolves an IDE (PyCharm 2023.2.3 PE) warning around
`urllib.parse.quote`, also enabling CTRL-click

libs/langchain/langchain/utilities/pubmed.py

@@ -2,6 +2,7 @@ import json
 import logging
 import time
 import urllib.error
+import urllib.parse
 import urllib.request
 from typing import Any, Dict, Iterator, List