docs(query-keys guide): change "And" to "An" (TanStack#3010)

Author: tshma

docs/src/pages/guides/query-keys.md

@@ -34,7 +34,7 @@ When a query needs more information to uniquely describe its data, you can use a
 useQuery(['todo', 5], ...)
 // queryKey === ['todo', 5]
 
-// And individual todo in a "preview" format
+// An individual todo in a "preview" format
 useQuery(['todo', 5, { preview: true }], ...)
 // queryKey === ['todo', 5, { preview: true }]