document neat matrix/irc tricks

howto/irc.md

@@ -815,6 +815,15 @@ Staff. Existing hardware resources can be reused.
 Matrix has bridges to IRC, which we currently use but are unreliable,
 see the [Matrix bridge disconnections](#matrix-bridge-disconnections) discussion.
 
+### IRC bridges *to* Matrix
+
+[matrix2051](https://github.com/progval/matrix2051) and [matrirc](https://github.com/martinetd/matrirc) are bridges that allow IRC clients to
+connect to Matrix.
+
+weechat also has a [matrix script](https://github.com/poljar/weechat-matrix) that allows weechat to talk with
+Matrix servers. It is reputed to be slow, and is being [rewritten in
+rust](https://github.com/poljar/weechat-matrix-rs).
+
 ### Discarded alternatives
 
 Most other alternatives have been discarded because they do not work