docs(select): Change select's openedChange output comment (#9934)

Author: julianobrasil

src/lib/select/select.ts

@@ -430,7 +430,7 @@ export class MatSelect extends _MatSelectMixinBase implements AfterContentInit,
       .pipe(take(1), switchMap(() => this.optionSelectionChanges));
   });
 
-   /** Event emitted when the select has been opened. */
+   /** Event emitted when the select panel has been toggled. */
    @Output() readonly openedChange: EventEmitter<boolean> = new EventEmitter<boolean>();
 
    /** Event emitted when the select has been opened. */