emails: Use the word email instead of message in do not reply sentence.

Fixes #13693

templates/zerver/emails/missed_message.source.html

@@ -37,7 +37,7 @@
     {% else %}
     <a href="{{ narrow_url }}">Reply in Zulip</a>, or <a href="{{ realm_uri }}/#settings/notifications">manage email preferences</a>.<br>
     <br>
-    Do not reply to this message. This Zulip server is not
+    Do not reply to this email. This Zulip server is not
     configured to accept incoming emails (<a href="https://zulip.readthedocs.io/en/latest/production/email-gateway.html">help</a>).
 
     {% endif %}

templates/zerver/emails/missed_message.txt

@@ -33,7 +33,7 @@ View or reply in Zulip:
 Reply in Zulip:
 {{ narrow_url }}
 
-Do not reply to this message. This Zulip server is not configured to accept
+Do not reply to this email. This Zulip server is not configured to accept
 incoming emails. Help:
 https://zulip.readthedocs.io/en/latest/production/email-gateway.html
 {% endif %}

version.py

@@ -26,4 +26,4 @@ LATEST_RELEASE_ANNOUNCEMENT = "https://blog.zulip.org/2019/12/13/zulip-2-1-relea
 #   historical commits sharing the same major version, in which case a
 #   minor version bump suffices.
 
-PROVISION_VERSION = '67.2'
+PROVISION_VERSION = '67.3'

zerver/tests/test_email_notifications.py

@@ -335,7 +335,7 @@ class TestMissedMessages(ZulipTestCase):
             self.example_email('hamlet'),
             'Extremely personal message!',
         )
-        verify_body_include = ['Do not reply to this message.']
+        verify_body_include = ['Do not reply to this email.']
         email_subject = 'PMs with Othello, the Moor of Venice'
         self._test_cases(msg_id, verify_body_include, email_subject, send_as_user)