MD Settings: ensure <a is="action-link"> have no :hover underline

chrome/browser/resources/settings/settings_shared_css.html

 <link rel="import" href="chrome://resources/cr_elements/shared_style_css.html">
 <link rel="import" href="/settings_root_css.html">
 
 <!-- Common styles for Material Design settings. -->
 <dom-module id="settings-shared">
   <template>
     <style include="cr-shared-style">
       h2 {
         align-items: center;
         display: flex;
@@ skipping 79 matching lines @@
       }
 
       paper-button.primary-button,
       paper-button.tertiary-button {
         --paper-button-flat-keyboard-focus: {
           background-color: rgba(51, 103, 214, .12);  /* --google-blue-700 */
         };
       }
 
       [is='action-link']:hover {
-        /* TODO(dbeam): check with bettes@ on this one, but I'm pretty sure we
-         * shouldn't be showing much :hover stuff on Polymer pages. */
         text-decoration: none;
       }
 
       /*
        * There are three main button styles, .primary-button, .secondary-button,
        * and .tertiary-button. The primary is the action button (e.g. "edit",
        * "delete") while the secondary is often a "Cancel" button. A tertiary
        * button may be used to get more information or similar, that we expect
        * most users will not need.
        */
@@ skipping 230 matching lines @@
 
       .favicon-image {
         background-repeat: no-repeat;
         background-size: contain;
         height: 16px;
         width: 16px;
       }
     </style>
   </template>
 </dom-module>