Highlight alert words in mentions you send to yourself.

Fixes #6946.

static/js/alert_words.js

@@ -14,7 +14,9 @@ function escape_user_regex(value) {
 }
 
 exports.process_message = function (message) {
-    if (!exports.notifies(message)) {
+    // Parsing for alert words is expensive, so we rely on the host
+    // to tell us there any alert words to even look for.
+    if (!message.alerted) {
         return;
     }
 
@@ -47,6 +49,10 @@ exports.process_message = function (message) {
 };
 
 exports.notifies = function (message) {
+    // We exclude ourselves from notifications when we type one of our own
+    // alert words into a message, just because that can be annoying for
+    // certain types of workflows where everybody on your team, including
+    // yourself, sets up an alert word to effectively mention the team.
     return !people.is_current_user(message.sender_email) && message.alerted;
 };
 

static/js/echo.js

@@ -230,6 +230,16 @@ exports.process_from_server = function process_from_server(messages) {
             sent_messages.mark_disparity(message.local_id);
         }
 
+        // Update our flags based on what the server gave us.
+        client_message.flags = message.flags;
+        message_store.set_message_booleans(client_message, client_message.flags);
+
+        // We don't try to highlight alert words locally, so we have to
+        // do it now.  (Note that we will indeed highlight alert words in
+        // messages that we sent to ourselves, since we might want to test
+        // that our alert words are set up correctly.)
+        alert_words.process_message(client_message);
+
         // Previously, the message had the "local echo" timestamp set
         // by the browser; if there was some round-trip delay to the
         // server, the actual server-side timestamp could be slightly