chore: fix link to source files in documentation (#5576)

Look like it was overlooked while moving source files.

docs/api.md

@@ -3898,7 +3898,7 @@ TimeoutError is emitted whenever certain operations are terminated due to timeou
 [Buffer]: https://nodejs.org/api/buffer.html#buffer_class_buffer "Buffer"
 [CDPSession]: #class-cdpsession  "CDPSession"
 [ChildProcess]: https://nodejs.org/api/child_process.html "ChildProcess"
-[ConnectionTransport]: ../lib/WebSocketTransport.js "ConnectionTransport"
+[ConnectionTransport]: ../src/WebSocketTransport.js "ConnectionTransport"
 [ConsoleMessage]: #class-consolemessage "ConsoleMessage"
 [Coverage]: #class-coverage "Coverage"
 [Dialog]: #class-dialog "Dialog"
@@ -3924,7 +3924,7 @@ TimeoutError is emitted whenever certain operations are terminated due to timeou
 [Touchscreen]: #class-touchscreen "Touchscreen"
 [Tracing]: #class-tracing "Tracing"
 [UIEvent.detail]: https://developer.mozilla.org/en-US/docs/Web/API/UIEvent/detail "UIEvent.detail"
-[USKeyboardLayout]: ../lib/USKeyboardLayout.js "USKeyboardLayout"
+[USKeyboardLayout]: ../src/USKeyboardLayout.js "USKeyboardLayout"
 [UnixTime]: https://en.wikipedia.org/wiki/Unix_time "Unix Time"
 [Worker]: #class-worker "Worker"
 [boolean]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type "Boolean"