[Extensions Docs] Remove default_state references from action API docs

The default_state boolean is something we haven't fully ironed out, and
some of the description of it was invalid (such as the icon always being
greyed out). Remove references to it.

Bug: None
Change-Id: Ib0daf369871cff8cae77816f0f66d98637b0f25c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2644072Reviewed-by: David Bertoni <dbertoni@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#846332}

chrome/common/extensions/api/action.json

@@ -5,7 +5,7 @@
 [
   {
     "namespace": "action",
-    "description": "Use actions to put icons in the main Google Chrome toolbar, to the right of the address bar. Actions can be set to take action on all pages (default_state: enabled) or only the current page (default_state: disabled). If an action is default disabled, the action appears grayed out when inactive. In addition to its <a href='action#icon'>icon</a>, an action can also have a <a href='action#tooltip'>tooltip</a>, a <a href='action#badge'>badge</a>, and a <a href='action#popups'>popup</a>.",
+    "description": "Use the <code>chrome.action</code> API to control the extension's icon in the Google Chrome toolbar.",
     "compiler_options": {
       "implemented_in": "chrome/browser/extensions/api/extension_action/extension_action_api.h"
     },