ui: hide DText "Formatting help" link in dialog boxes.

Hide the "Formatting help" link for single-line DText fields in dialog boxes, such as after the
"Reason" field in the flag, appeal, and report dialog boxes.

app/javascript/src/styles/common/simple_form.scss

@@ -154,14 +154,14 @@ form.one-line-form {
 }
 
 div.ui-dialog {
-  textarea, input[type="text"] {
-    width: 100%;
-    max-width: 100%;
-  }
-
   form.simple_form {
     margin-bottom: 0;
 
+    textarea, input[type="text"] {
+      width: 100%;
+      max-width: 100%;
+    }
+
     div.input {
       margin-bottom: 0.5em;
     }
@@ -169,6 +169,10 @@ div.ui-dialog {
     div.input.hidden {
       display: none;
     }
+
+    div.dtext-inline span.dtext-hint {
+      display: none;
+    }
   }
 
   /* the submit and close buttons */