me_messages: Improve grid, layout.

web/styles/message_row.css

@@ -291,6 +291,10 @@
                     --message-box-avatar-height
                 )
                 minmax(0, auto) repeat(3, auto);
+            /* We align items to the baseline on me messages,
+               and unset the align-content property. */
+            align-items: baseline;
+            align-content: unset;
 
             .message-avatar {
                 /* Set the line-height to match the height of the avatar image
@@ -316,6 +320,11 @@
                 align-self: center;
             }
 
+            .message_edit_notice {
+                /* Unset the margin on a typical sender line. */
+                margin-left: 0;
+            }
+
             .message_sender {
                 /* Don't display message sender as flexbox for me-messages. */
                 display: block;