docs: Update Page.target deprecation message to cover broader usage. (#15108)

Co-authored-by: Piotr Paulski <[email protected]>

docs/api/puppeteer.page.md

@@ -1347,7 +1347,7 @@ A target this page was created from.
 
 **Deprecated:**
 
-Use [Page.createCDPSession()](./puppeteer.page.createcdpsession.md) directly.
+To create CDP session use [Page.createCDPSession()](./puppeteer.page.createcdpsession.md) directly. To identify pages spawned by this one, use [PageEvent.Popup](./puppeteer.pageevent.md) event instead.
 
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 <tr><td>

docs/api/puppeteer.page.target.md

@@ -6,7 +6,7 @@ sidebar_label: Page.target
 
 > Warning: This API is now obsolete.
 >
-> Use [Page.createCDPSession()](./puppeteer.page.createcdpsession.md) directly.
+> To create CDP session use [Page.createCDPSession()](./puppeteer.page.createcdpsession.md) directly. To identify pages spawned by this one, use [PageEvent.Popup](./puppeteer.pageevent.md) event instead.
 
 A target this page was created from.
 

packages/puppeteer-core/src/api/Page.ts

@@ -910,7 +910,8 @@ export abstract class Page extends EventEmitter<PageEvents> {
   /**
    * A target this page was created from.
    *
-   * @deprecated Use {@link Page.createCDPSession} directly.
+   * @deprecated To create CDP session use {@link Page.createCDPSession} directly. To
+   * identify pages spawned by this one, use {@link PageEvent.Popup} event instead.
    */
   abstract target(): Target;