tform: Add `@since` to doc of `MouseWatcher::is_raw_button_down()`

panda/src/tform/mouseWatcher.I

@@ -147,6 +147,8 @@ is_button_down(ButtonHandle button) const {
 /**
  * Similar to is_button_down(), but uses the raw button handle as reported by
  * the raw- prefixed events, and is not subject to the inactivity timer.
+ *
+ * @since 1.11.0
  */
 INLINE bool MouseWatcher::
 is_raw_button_down(ButtonHandle button) const {