Docs: fix arg name of toggled signal in BaseButton

arg was renamed in #15530 but the description wasn't updated

doc/classes/BaseButton.xml

@@ -92,7 +92,7 @@
 			<argument index="0" name="button_pressed" type="bool">
 			</argument>
 			<description>
-				This signal is emitted when the button was just toggled between pressed and normal states (only if toggle_mode is active). The new state is contained in the [i]pressed[/i] argument.
+				This signal is emitted when the button was just toggled between pressed and normal states (only if toggle_mode is active). The new state is contained in the [i]button_pressed[/i] argument.
 			</description>
 		</signal>
 	</signals>