Add issue references to things

Author: turt2live

res/css/_common.scss

@@ -273,6 +273,7 @@ textarea {
 // TODO: Review mx_GeneralButton usage to see if it can use a different class
 // These classes were brought in from the old UserSettings and are included here to avoid
 // breaking the app.
+// Ref: https://github.com/vector-im/riot-web/issues/8420
 .mx_GeneralButton {
     @mixin mx_DialogButton;
     display: inline;

src/UserSettingsStore.js

@@ -18,6 +18,7 @@ limitations under the License.
 import MatrixClientPeg from './MatrixClientPeg';
 
 // TODO: Decommission.
+// Ref: https://github.com/vector-im/riot-web/issues/8424
 export default {
     /*
      * Returns the email pusher (pusher of type 'email') for a given

src/components/views/room_settings/ColorSettings.js

@@ -41,6 +41,7 @@ const ROOM_COLORS = [
 
 // Dev note: this component is not attached anywhere, but is left here as it
 // has a high possibility of being used in the nearish future.
+// Ref: https://github.com/vector-im/riot-web/issues/8421
 
 module.exports = React.createClass({
     displayName: 'ColorSettings',