css class should be warn-tio not warn

Author: EvieePy

docs/getting-started/installing.rst

@@ -106,7 +106,7 @@ Extra and Optional Dependencies
 
 .. raw:: html
 
-    <span class="warn">This version of TwitchIO is an Beta Version!</span>
+    <span class="warn-tio">This version of TwitchIO is an Beta Version!</span>
     <hr></hr>