Update reference.ts

Author: schmidt-sebastian

packages/firestore/src/lite-api/reference.ts

@@ -94,11 +94,11 @@ export type UpdateData<T> = T extends Primitive
  * @param merge - Changes the behavior of a `setDoc()` call to only replace the
  * values specified in its data argument. Fields omitted from the `setDoc()`
  * call remain untouched. If your input sets any field to an empty map, all
- * nested fields at this location are overwritten.
+ * nested fields are overwritten.
  * @param mergeFields - Changes the behavior of `setDoc()` calls to only replace
  * the specified field paths. Any field path that is not specified is ignored
  * and remains untouched. If your input sets any field to an empty map, all
- * nested fields at this location are overwritten.
+ * nested fields are overwritten.
  */
 export type SetOptions =
   | {