Rename beforeCreateAnnotation to createAnnotation

This is the event that creates the annotation, so it is better to name
it in a more obvious way.

Context:
#3829 (comment)

src/annotator/annotation-sync.js

@@ -70,7 +70,7 @@ export class AnnotationSync {
       if (annotation.$tag) {
         return;
       }
-      this.bridge.call('beforeCreateAnnotation', this._format(annotation));
+      this.bridge.call('createAnnotation', this._format(annotation));
     });
   }
 

src/annotator/test/annotation-sync-test.js

@@ -108,7 +108,7 @@ describe('AnnotationSync', () => {
 
   describe('handling events from the annotator', () => {
     describe('on "beforeAnnotationCreated" event', () => {
-      it('calls "beforeCreateAnnotation" RPC method in the sidebar', () => {
+      it('calls "createAnnotation" RPC method in the sidebar', () => {
         // nb. Setting an empty `$tag` here matches what `Guest#createAnnotation`
         // does.
         const ann = { id: 1, $tag: '' };
@@ -117,7 +117,7 @@ describe('AnnotationSync', () => {
         emitter.publish('beforeAnnotationCreated', ann);
 
         assert.called(fakeBridge.call);
-        assert.calledWith(fakeBridge.call, 'beforeCreateAnnotation', {
+        assert.calledWith(fakeBridge.call, 'createAnnotation', {
           msg: ann,
           tag: ann.$tag,
         });

src/sidebar/services/frame-sync.js

@@ -144,7 +144,7 @@ export class FrameSyncService {
      */
     this._setupSyncFromGuests = () => {
       // A new annotation, note or highlight was created in the frame
-      this._guestRPC.on('beforeCreateAnnotation', event => {
+      this._guestRPC.on('createAnnotation', event => {
         const annot = Object.assign({}, event.msg, { $tag: event.tag });
         // If user is not logged in, we can't really create a meaningful highlight
         // or annotation. Instead, we need to open the sidebar, show an error,

src/sidebar/services/test/frame-sync-test.js

@@ -316,7 +316,7 @@ describe('FrameSyncService', () => {
         fakeStore.isLoggedIn.returns(true);
         const ann = { target: [] };
 
-        guestBridge().emit('beforeCreateAnnotation', { tag: 't1', msg: ann });
+        guestBridge().emit('createAnnotation', { tag: 't1', msg: ann });
 
         assert.calledWith(
           fakeAnnotationsService.create,
@@ -337,28 +337,28 @@ describe('FrameSyncService', () => {
       it('should not create an annotation in the sidebar', () => {
         const ann = { target: [] };
 
-        guestBridge().emit('beforeCreateAnnotation', { tag: 't1', msg: ann });
+        guestBridge().emit('createAnnotation', { tag: 't1', msg: ann });
 
         assert.notCalled(fakeAnnotationsService.create);
       });
 
       it('should open the sidebar', () => {
         const ann = { target: [] };
-        guestBridge().emit('beforeCreateAnnotation', { tag: 't1', msg: ann });
+        guestBridge().emit('createAnnotation', { tag: 't1', msg: ann });
 
         assert.calledWith(hostBridge().call, 'openSidebar');
       });
 
       it('should open the login prompt panel', () => {
         const ann = { target: [] };
-        guestBridge().emit('beforeCreateAnnotation', { tag: 't1', msg: ann });
+        guestBridge().emit('createAnnotation', { tag: 't1', msg: ann });
 
         assert.calledWith(fakeStore.openSidebarPanel, 'loginPrompt');
       });
 
       it('should send a "deleteAnnotation" message to the frame', () => {
         const ann = { target: [] };
-        guestBridge().emit('beforeCreateAnnotation', { tag: 't1', msg: ann });
+        guestBridge().emit('createAnnotation', { tag: 't1', msg: ann });
 
         assert.calledWith(guestBridge().call, 'deleteAnnotation');
       });

src/types/bridge-events.d.ts

@@ -29,7 +29,7 @@ export type GuestToSidebarEvent =
   /**
    * The guest is asking the sidebar to create an annotation.
    */
-  | 'beforeCreateAnnotation'
+  | 'createAnnotation'
 
   /**
    * The guest is asking the sidebar to relay the message to open the sidebar.