EventIndexing: Rename our EventIndexer class.

src/EventIndexing.js

@@ -20,7 +20,7 @@ import MatrixClientPeg from "./MatrixClientPeg";
 /**
  * Event indexing class that wraps the platform specific event indexing.
  */
-export default class EventIndexer {
+export default class EventIndex {
     constructor() {
         this.crawlerCheckpoints = [];
         // The time that the crawler will wait between /rooms/{room_id}/messages