Rename components/sync/js/README.js to README.

README.js is clearly not holding JS contents, and is causing ESLint
errors.

This is in preparation of turning on ESLint PRESUBMIT checks for
src/components.

Bug: 1019312
Change-Id: Id32353b0f1e4bcd1cc62bd3983739c16fe0d24bd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1898868
Commit-Queue: Marc Treib <treib@chromium.org>
Auto-Submit: Demetrios Papadopoulos <dpapad@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712489}

components/sync/js/js_backend.h

@@ -5,7 +5,7 @@
 #ifndef COMPONENTS_SYNC_JS_JS_BACKEND_H_
 #define COMPONENTS_SYNC_JS_JS_BACKEND_H_
 
-// See README.js for design comments.
+// See README for design comments.
 
 #include <string>
 

components/sync/js/js_controller.h

@@ -5,7 +5,7 @@
 #ifndef COMPONENTS_SYNC_JS_JS_CONTROLLER_H_
 #define COMPONENTS_SYNC_JS_JS_CONTROLLER_H_
 
-// See README.js for design comments.
+// See README for design comments.
 
 #include <string>
 

components/sync/js/js_event_details.h

@@ -5,7 +5,7 @@
 #ifndef COMPONENTS_SYNC_JS_JS_EVENT_DETAILS_H_
 #define COMPONENTS_SYNC_JS_JS_EVENT_DETAILS_H_
 
-// See README.js for design comments.
+// See README for design comments.
 
 #include <string>
 

components/sync/js/js_event_handler.h

@@ -5,7 +5,7 @@
 #ifndef COMPONENTS_SYNC_JS_JS_EVENT_HANDLER_H_
 #define COMPONENTS_SYNC_JS_JS_EVENT_HANDLER_H_
 
-// See README.js for design comments.
+// See README for design comments.
 
 #include <string>