Fixes and improvements for v1.3 documentation

* Add missing versionadded strings for v1.3
* Add missing versionchanged string for Message.edit
* Consistently use versionadded for attributes
* Consistently use versionchanged for parameters
* Use versionchanged for Bot.is_owner
* Fix references in v1.3 changelog
* Improve grammar in v1.3 changelog

docs/api.rst

@@ -768,9 +768,15 @@ Profile
     .. attribute:: team_user
 
         A boolean indicating if the user is in part of a team.
+
+        .. versionadded:: 1.3
+
     .. attribute:: system
 
         A boolean indicating if the user is officially part of the Discord urgent message system.
+
+        .. versionadded:: 1.3
+
     .. attribute:: mutual_guilds
 
         A list of :class:`Guild` that the :class:`ClientUser` shares with this
@@ -914,12 +920,6 @@ of :class:`enum.Enum`.
 
     Specifies the region a voice server belongs to.
 
-    .. versionchanged:: 1.2
-        The ``india`` region was added.
-
-    .. versionchanged:: 1.3
-        The ``europe`` and ``dubai`` regions were added.
-
     .. attribute:: amsterdam
 
         The Amsterdam region.
@@ -929,6 +929,9 @@ of :class:`enum.Enum`.
     .. attribute:: dubai
 
         The Dubai region.
+
+        .. versionadded:: 1.3
+
     .. attribute:: eu_central
 
         The EU Central region.
@@ -938,6 +941,9 @@ of :class:`enum.Enum`.
     .. attribute:: europe
 
         The Europe region.
+
+        .. versionadded:: 1.3
+
     .. attribute:: frankfurt
 
         The Frankfurt region.
@@ -947,6 +953,9 @@ of :class:`enum.Enum`.
     .. attribute:: india
 
         The India region.
+
+        .. versionadded:: 1.2
+
     .. attribute:: japan
 
         The Japan region.
@@ -1332,6 +1341,8 @@ of :class:`enum.Enum`.
         - ``channel``: A :class:`TextChannel` or :class:`Object` with the channel ID where the members were moved.
         - ``count``: An integer specifying how many members were moved.
 
+        .. versionadded:: 1.3
+
     .. attribute:: member_disconnect
 
         A member's voice state has changed. This triggers when a
@@ -1342,6 +1353,8 @@ of :class:`enum.Enum`.
 
         - ``count``: An integer specifying how many members were disconnected.
 
+        .. versionadded:: 1.3
+
     .. attribute:: bot_add
 
         A bot was added to the guild.
@@ -1349,6 +1362,8 @@ of :class:`enum.Enum`.
         When this is the action, the type of :attr:`~AuditLogEntry.target` is
         the :class:`Member` or :class:`User` which was added to the guild.
 
+        .. versionadded:: 1.3
+
     .. attribute:: role_create
 
         A new role was created.
@@ -1540,6 +1555,8 @@ of :class:`enum.Enum`.
 
         - ``count``: An integer specifying how many messages were deleted.
 
+        .. versionadded:: 1.3
+
     .. attribute:: message_pin
 
         A message was pinned in a channel.
@@ -1553,6 +1570,8 @@ of :class:`enum.Enum`.
         - ``channel``: A :class:`TextChannel` or :class:`Object` with the channel ID where the message was pinned.
         - ``message_id``: the ID of the message which was pinned.
 
+        .. versionadded:: 1.3
+
     .. attribute:: message_unpin
 
         A message was unpinned in a channel.
@@ -1566,6 +1585,8 @@ of :class:`enum.Enum`.
         - ``channel``: A :class:`TextChannel` or :class:`Object` with the channel ID where the message was unpinned.
         - ``message_id``: the ID of the message which was unpinned.
 
+        .. versionadded:: 1.3
+
     .. attribute:: integration_create
 
         A guild integration was created.
@@ -1573,6 +1594,8 @@ of :class:`enum.Enum`.
         When this is the action, the type of :attr:`~AuditLogEntry.target` is
         the :class:`Object` with the integration ID of the integration which was created.
 
+        .. versionadded:: 1.3
+
     .. attribute:: integration_update
 
         A guild integration was updated.
@@ -1580,6 +1603,8 @@ of :class:`enum.Enum`.
         When this is the action, the type of :attr:`~AuditLogEntry.target` is
         the :class:`Object` with the integration ID of the integration which was updated.
 
+        .. versionadded:: 1.3
+
     .. attribute:: integration_delete
 
         A guild integration was deleted.
@@ -1587,6 +1612,8 @@ of :class:`enum.Enum`.
         When this is the action, the type of :attr:`~AuditLogEntry.target` is
         the :class:`Object` with the integration ID of the integration which was deleted.
 
+        .. versionadded:: 1.3
+
 .. class:: AuditLogActionCategory
 
     Represents the category that the :class:`AuditLogAction` belongs to.
@@ -1721,6 +1748,8 @@ of :class:`enum.Enum`.
 
     Represents the membership state of a team member retrieved through :func:`Bot.application_info`.
 
+    .. versionadded:: 1.3
+
     .. attribute:: invited
 
         Represents an invited member.
@@ -1733,6 +1762,8 @@ of :class:`enum.Enum`.
 
 	Represents the type of webhook that can be received.
 
+    .. versionadded:: 1.3
+
 	.. attribute:: incoming
 
 		Represents a webhook that can post messages to channels with a token.