message: Implement `State::get` in `pane_grid`
diff: @@ -82,6 +82,14 @@ impl<T> State<T> {
  /// Returns the internal state of the given [`Pane`], if it exists.
  ///
  /// [`Pane`]: struct.Pane.html
  + pub fn get(&self, pane: &Pane) -> Option<&T> {
  + self.panes.get(pane)
  + }
  +
  + /// Returns the internal state of the given [`Pane`] with mutability, if it
  + /// exists.
  + ///
  + /// [`Pane`]: struct.Pane.html
  pub fn get_mut(&mut self, pane: &Pane) -> Option<&mut T> {
  self.panes.get_mut(pane)
  }
  