Make null m.room.name behaviour explicit

PR feedback

event-schemas/schema/m.room.canonical_alias

@@ -6,8 +6,8 @@ description: |-
     considered the canonical one. This could be for display purposes or as
     suggestion to users which alias to use to advertise the room.
 
-    A room with an ``m.room.canonical_alias`` event with an empty or absent
+    A room with an ``m.room.canonical_alias`` event with an absent, null, or
-    ``alias`` field should be treated the same as a room with no
+    empty ``alias`` field should be treated the same as a room with no
     ``m.room.canonical_alias`` event.
 properties:
   content:

event-schemas/schema/m.room.name

@@ -7,8 +7,9 @@ description: |-
     is a human-friendly string designed to be displayed to the end-user. The
     room name is not unique, as multiple rooms can have the same room name set.
 
-    A room with an ``m.room.name`` event with an absent or empty ``name`` field
+    A room with an ``m.room.name`` event with an absent, null, or empty
-    should be treated the same as a room with no ``m.room.name`` event.
+    ``name`` field should be treated the same as a room with no ``m.room.name``
+    event.
 
     An event of this type is automatically created when creating a room using
     ``/createRoom`` with the ``name`` key.