show warning message for locked account

app/javascript/styles/mastodon/containers.scss

@@ -229,6 +229,12 @@
       min-height: 1px;
     }
 
+    h2 {
+      font-size: 1rem;
+      align-items: center;
+      display: flex;
+    }
+
     .nav-left {
       display: flex;
       align-items: stretch;

app/views/accounts/show.html.haml

@@ -23,6 +23,11 @@
 
 = render 'header', account: @account, with_bio: true
 
+- if @account.user&.disabled?
+  .header
+    .nav-center
+      %h2 This user's account has been locked by a moderator.
+
 .grid
   .column-0
     .h-feed