docs: document addgossip API.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Added: JSON-RPC: `addgossip` allows direct injection of network gossip messages.

doc/Makefile

@@ -7,6 +7,7 @@ doc-wrongdir:
 MANPAGES := doc/lightning-cli.1 \
 	doc/lightningd.8 \
 	doc/lightningd-config.5 \
+	doc/lightning-addgossip.7 \
 	doc/lightning-autocleaninvoice.7 \
 	doc/lightning-check.7 \
 	doc/lightning-checkmessage.7 \

doc/index.rst

@@ -29,6 +29,7 @@ c-lightning Documentation
    :maxdepth: 1
    :caption: Manpages
 
+   lightning-addgossip <lightning-addgossip.7.md>
    lightning-autocleaninvoice <lightning-autocleaninvoice.7.md>
    lightning-check <lightning-check.7.md>
    lightning-checkmessage <lightning-checkmessage.7.md>

doc/lightning-addgossip.7.md

@@ -0,0 +1,41 @@
+lightning-addgossip -- Command for injecting a gossip message (low-level)
+===============================================================
+
+SYNOPSIS
+--------
+
+**addgossip** *message*
+
+DESCRIPTION
+-----------
+
+The **addgossip** RPC command injects a hex-encoded gossip message into
+the gossip daemon.  It may return an error if it is malformed, or may
+update its internal state using the gossip message.
+
+Note that currently some paths will still silently reject the gossip: it
+is best effort.
+
+This is particularly used by plugins which may receive channel_update
+messages within error replies.
+
+RETURN VALUE
+------------
+
+On success, an empty object is returned.
+
+AUTHOR
+------
+
+Rusty Russell <<rusty@rustcorp.com.au>> is mainly responsible.
+
+SEE ALSO
+--------
+
+lightning-pay(7)
+
+RESOURCES
+---------
+
+Main web site: <https://github.com/ElementsProject/lightning>
+