Merge #18957: Add a link from ZMQ doc to ZMQ example in contrib/

d97fac4 Add a link from ZMQ doc to ZMQ example in contrib/ (Damian Mee)

Pull request description:

  No code changes :).  Only a small convenience improvement in zmq doc.

ACKs for top commit:
  fanquake:
    ACK d97fac4

Tree-SHA512: f05a8a7a77c0a698637fd24ffc94d0d617743b434f46695a56576a53331ede254aeece416baf3f8275ae4dfad85ae6e14d1920aa32af53150847420a176d90fb

Author: fanquake

doc/zmq.md

@@ -96,7 +96,7 @@ ZeroMQ endpoint specifiers for TCP (and others) are documented in the
 Client side, then, the ZeroMQ subscriber socket must have the
 ZMQ_SUBSCRIBE option set to one or either of these prefixes (for
 instance, just `hash`); without doing so will result in no messages
-arriving. Please see `contrib/zmq/zmq_sub.py` for a working example.
+arriving. Please see [`contrib/zmq/zmq_sub.py`](/contrib/zmq/zmq_sub.py) for a working example.
 
 ## Remarks