Update .eslintrc.yml

added Extension to ignored var names

Author: GrylledCheez

.eslintrc.yml

@@ -175,7 +175,7 @@ rules:
   no-unused-vars:
     - error
     # Vars use a suffix _ instead of a prefix because of file-scope private vars
-    - varsIgnorePattern: (^unused|Manager|fillPreferencesWindow|enable|disable|init|_$)
+    - varsIgnorePattern: (^unused|Manager|fillPreferencesWindow|enable|disable|init|Extension|_$)
       argsIgnorePattern: ^(unused|_)
   no-useless-call: error
   no-useless-computed-key: error