fix(docs): fix typo in firestore query docs (prescottprue#721)

Author: giraffesyo

docs/firestore.md

@@ -111,7 +111,7 @@ Firestore queries can be created in two ways:
 
 ## Manual {#manual}
 
-If you want to trigger a query based on a click or mange listeners yourself, you can use `setListener` or `setListeners`. When doing this, make sure you call `unsetLister` for each listener you set.
+If you want to trigger a query based on a click or mange listeners yourself, you can use `setListener` or `setListeners`. When doing this, make sure you call `unsetListener` for each listener you set.
 
 ##### Component Class