Fix membership state names
It's called 'join', not 'joined'.
@@ -520,7 +520,7 @@ the state of the room.
#. If ``membership`` is ``invite``:
- i. If the ``sender``'s current membership state is not ``joined``, reject.
+ i. If the ``sender``'s current membership state is not ``join``, reject.
#. If *target user*'s current membership state is ``join`` or ``ban``,
reject.
@@ -535,7 +535,7 @@ the state of the room.
i. If the ``sender`` matches ``state_key``, allow if and only if that user's
current membership state is ``invite`` or ``join``.
- #. If the ``sender``'s current membership state is not ``joined``, reject.
+ #. If the ``sender``'s current membership state is not ``join``, reject.
#. If the *target user*'s current membership state is ``ban``, and the
``sender``'s power level is less than the *ban level*, reject.
@@ -548,7 +548,7 @@ the state of the room.
#. If ``membership`` is ``ban``:
- i. If the ``sender``'s current membership state is not ``joined``, reject.
+ i. If the ``sender``'s current membership state is not ``join``, reject.
#. If the ``sender``'s power level is greater than or equal to the *ban
level*, and the *target user*'s power level is less than the
@@ -558,7 +558,7 @@ the state of the room.
#. Otherwise, the membership is unknown. Reject.
-#. If the ``sender``'s current membership state is not ``joined``, reject.
+#. If the ``sender``'s current membership state is not ``join``, reject.
#. If the event type's *required power level* is greater than the ``sender``'s power
level, reject.
