Allow extensions to remove and override the bookmark shortcut key

chrome/common/extensions/docs/templates/json/manifest.json

 {
   "app": {
     "documentation": "manifest/app.html",
     "example": {},
     "level": "required"
   },
   "app.background": {
     "example": {"scripts": ["background.js"]},
     "level": "required"
   },
   "background": {
     "documentation": "background_pages.html"
   },
   "background.persistent": {
     "documentation": "event_pages.html",
     "example": false,
     "level": "recommended"
   },
   "browser_action": {
     "documentation": "browserAction.html",
     "example": {},
     "level": "only_one"
   },
+  "chrome_settings_overrides": {
+    "documentation": "settings_override.html",
+    "example": {}
+  },
   "chrome_url_overrides": {
     "documentation": "override.html",
     "example": {}
   },
   "content_scripts": {
     "documentation": "content_scripts.html",
     "example": [{}]
   },
   "content_security_policy": {
     "documentation": "contentSecurityPolicy.html",
@@ skipping 133 matching lines @@
   "version": {
     "documentation": "manifest/version.html",
     "example": "versionString",
     "level": "required"
   },
   "web_accessible_resources": {
     "documentation": "manifest/web_accessible_resources.html",
     "example": []
   }
 }