Add the message correction note

doc/source/commands.rst

@@ -223,6 +223,11 @@ These commands will work in any conversation tab (MultiUserChat, Private, or
 .. glossary::
     :sorted:
 
+    /correct
+        **Usage:** ``/correct <corrected message>``
+
+        Replace the content of the last sent message with *corrected message*.
+
     /say
         **Usage:** ``/say <message>``
 

doc/source/misc/correct.rst

@@ -0,0 +1,24 @@
+Message Correction
+==================
+
+Poezio implements the `XEP-0308`_
+which allows the correction of the last message sent.
+
+The corrections are signalled with a number append to the nick of the user, in
+a different color.
+
+.. figure:: ../images/correct.png
+    :alt: Corrected message
+
+The **9** here represents the number of times this message has been corrected.
+
+
+You can show the revisions of a message by loading the
+*display_corrections* plugin, and you
+can correct your own messages with the :term:`/correct` command.
+
+
+.. note:: Please do not abuse of this feature, as it will simply be displayed as
+            another plain message in the clients that do not support correction.
+
+.. _XEP-0308: http://xmpp.org/extensions/xep-0308.html

doc/source/misc/index.rst

@@ -6,6 +6,7 @@ Contents:
 .. toctree::
     :maxdepth: 2
 
+    correct
     ssl