fixup! Bug 40925: Implemented the Security Level component

Bug 42667: Add the "description-deemphasized" class to our preferences.

browser/components/securitylevel/content/securityLevelPreferences.inc.xhtml

@@ -6,7 +6,7 @@
     <html:h2 data-l10n-id="security-level-preferences-heading"></html:h2>
   </label>
   <vbox flex="1">
-    <description flex="1">
+    <description class="description-deemphasized" flex="1">
       <html:span
         id="securityLevel-overview"
         class="tail-with-learn-more"