Added options description.

_locales/en/messages.json

@@ -350,5 +350,8 @@
     },
     "supportInvidiousDescription": {
         "message": "Invidious (invidio.us) is a third party YouTube client. To enable support, you must accept the extra permissions. This does NOT work in incongnito on chrome and other chromium variants."
+    },
+    "optionsInfo": {
+        "message": "Enable Invidious support, disable autoskip, hide buttons and more."
     }
 }

popup.html

@@ -195,6 +195,11 @@
               <button id="optionsButton" class="dangerButton popupElement">__MSG_Options__</button>
 
               <br/>
+              
+              <sub class="popupElement">
+                __MSG_optionsInfo__
+              </sub>
+
               <br/>
           </div>