Fixed missing comma in example on where.md (#1638)

Author: ELowry

content/collections/modifiers/where.md

@@ -54,7 +54,7 @@ You can also pass an operator to the modifier, so you can do checks like "where
 
 ```
 <h2>I hate...</h2>
-{{ games | where('feeling', '!=' 'love') }}
+{{ games | where('feeling', '!=', 'love') }}
   {{ title }}<br>
 {{ /games }}
 ```