Fix MSC reference

proposals/2240-rooms-v6.md

@@ -4,7 +4,7 @@ A new room version, `6`, is proposed using [room version 5](https://matrix.org/d
 and incorporating the following MSCs:
 
 * [MSC2209](https://github.com/matrix-org/matrix-doc/pull/2209) - Including notifications in power level auth rules.
-* [MSC2212](https://github.com/matrix-org/matrix-doc/pull/2432) - Alias event authorisation and redaction.
+* [MSC2432](https://github.com/matrix-org/matrix-doc/pull/2432) - Alias event authorisation and redaction.
 * [MSC2540](https://github.com/matrix-org/matrix-doc/pull/2540) - Integers in canonical JSON compliance.
 
 Though other MSCs are capable of being included in this version, they do not have sufficient implementation to be