doc: add tor.md section on how to get tor info via bitcoind

Author: jonatack

doc/tor.md

@@ -5,6 +5,16 @@ It is possible to run Bitcoin Core as a Tor onion service, and connect to such s
 The following directions assume you have a Tor proxy running on port 9050. Many distributions default to having a SOCKS proxy listening on port 9050, but others may not. In particular, the Tor Browser Bundle defaults to listening on port 9150. See [Tor Project FAQ:TBBSocksPort](https://www.torproject.org/docs/faq.html.en#TBBSocksPort) for how to properly
 configure Tor.
 
+## How to see information about your Tor configuration via Bitcoin Core
+
+There are several ways to see your local onion address in Bitcoin Core:
+- in the debug log (grep for "tor:" or "AddLocal")
+- in the output of RPC `getnetworkinfo` in the "localaddresses" section
+- in the output of the CLI `-netinfo` peer connections dashboard
+
+You may set the `-debug=tor` config logging option to have additional
+information in the debug log about your Tor configuration.
+
 
 ## 1. Run Bitcoin Core behind a Tor proxy