Bug 43117: Hide "Always underline links" from settings.

browser/components/preferences/main.inc.xhtml

@@ -746,7 +746,8 @@
 #endif
   <checkbox id="alwaysUnderlineLinks"
             data-l10n-id="browsing-always-underline-links"
-            preference="layout.css.always_underline_links"/>
+            preference="layout.css.always_underline_links"
+            hidden="true"/>
   <checkbox id="searchStartTyping"
             data-l10n-id="browsing-search-on-start-typing"
             preference="accessibility.typeaheadfind"/>