Wording fixes

proposals/2366-key-verification-accept.md

@@ -31,7 +31,7 @@ types are already described in [MSC2241 (Key verification in
 DMs)](https://github.com/matrix-org/matrix-doc/pull/2241).  This proposal adds
 them to verifications in to-device messages.
 
-The first event type is `m.key.verification.ready`, which may be sent by the
+The first event type is `m.key.verification.ready`, which must be sent by the
 target of the `m.key.verification.request` message, upon receipt of the
 `m.key.verification.request` event.  It has the fields:
 
@@ -47,7 +47,7 @@ After the `m.key.verification.ready` event is sent, either party can send an
 `m.key.verification.start` event to begin the verification.  If both parties
 send an `m.key.verification.start` event, and they both specify the same
 verification method, then the event sent by the user whose user ID is the
-smallest is used, and the other `m.key.verification.start` event is ignored.
+lexicographically smallest is used, and the other `m.key.verification.start` event is ignored.
 In the case of a single user verifying two of their devices, the device ID is
 compared instead.  If both parties send an `m.key.verification.start` event,
 but they specify different verification methods, the verification should be