PYTHON-5155 Use dochub link for fork warning (#2173)

Author: ShaneHarvey

doc/changelog.rst

@@ -199,7 +199,7 @@ PyMongo 4.9 brings a number of improvements including:
   unction-as-a-service (FaaS) like AWS Lambda, Google Cloud Functions, and Microsoft Azure Functions.
   On some FaaS systems, there is a ``fork()`` operation at function
   startup.  By delaying the connection to the first operation, we avoid a deadlock.  See
-  `Is PyMongo Fork-Safe`_ for more information.
+  :ref:`pymongo-fork-safe` for more information.
 
 
 Issues Resolved
@@ -208,7 +208,6 @@ Issues Resolved
 See the `PyMongo 4.9 release notes in JIRA`_ for the list of resolved issues
 in this release.
 
-.. _Is PyMongo Fork-Safe: https://www.mongodb.com/docs/languages/python/pymongo-driver/current/troubleshooting/#forking-a-process-causes-a-deadlock
 .. _PyMongo 4.9 release notes in JIRA: https://jira.mongodb.org/secure/ReleaseNote.jspa?projectId=10004&version=39940
 
 

pymongo/asynchronous/topology.py

@@ -236,7 +236,7 @@ async def open(self) -> None:
             warnings.warn(  # type: ignore[call-overload] # noqa: B028
                 "AsyncMongoClient opened before fork. May not be entirely fork-safe, "
                 "proceed with caution. See PyMongo's documentation for details: "
-                "https://www.mongodb.com/docs/languages/python/pymongo-driver/current/troubleshooting/#forking-a-process-causes-a-deadlock",
+                "https://dochub.mongodb.org/core/pymongo-fork-deadlock",
                 **kwargs,
             )
             async with self._lock:

pymongo/synchronous/topology.py

@@ -236,7 +236,7 @@ def open(self) -> None:
             warnings.warn(  # type: ignore[call-overload] # noqa: B028
                 "MongoClient opened before fork. May not be entirely fork-safe, "
                 "proceed with caution. See PyMongo's documentation for details: "
-                "https://www.mongodb.com/docs/languages/python/pymongo-driver/current/troubleshooting/#forking-a-process-causes-a-deadlock",
+                "https://dochub.mongodb.org/core/pymongo-fork-deadlock",
                 **kwargs,
             )
             with self._lock: