feat(page): mark page.client() as internal (#7585)

This PR marks the .client() method as internal since
we don't encourage our users to use it.

docs/api.md

@@ -133,7 +133,6 @@
   * [page.browser()](#pagebrowser)
   * [page.browserContext()](#pagebrowsercontext)
   * [page.click(selector[, options])](#pageclickselector-options)
-  * [page.client()](#pageclient)
   * [page.close([options])](#pagecloseoptions)
   * [page.content()](#pagecontent)
   * [page.cookies([...urls])](#pagecookiesurls)
@@ -1466,12 +1465,6 @@ const [response] = await Promise.all([
 
 Shortcut for [page.mainFrame().click(selector[, options])](#frameclickselector-options).
 
-#### page.client()
-
-- returns: <[CDPSession]>
-
-Get the CDP session client the page belongs to.
-
 #### page.close([options])
 
 - `options` <[Object]>

src/common/Page.ts

@@ -731,6 +731,7 @@ export class Page extends EventEmitter {
 
   /**
    * Get the CDP session client the page belongs to.
+   * @internal
    */
   client(): CDPSession {
     return this._client;

utils/doclint/check_public_api/index.js

@@ -25,6 +25,7 @@ const {
 const EXCLUDE_PROPERTIES = new Set([
   'Browser.create',
   'Headers.fromPayload',
+  'Page.client',
   'Page.create',
   'JSHandle.toString',
   'TimeoutError.name',