Add basic examples

src/lib.rs

+///
+/// `get_widget!` allows retrieving a widget from a gtk::Builder
+///
+/// Example 1:
+///
+/// ```no_run
+/// let builder = gtk::Builder::new_from_resource("/org/gnome/App/ui/widget.ui");
+/// get_widget!(builder, gtk::Label, my_label);
+/// my_label.set_text("Salut world");
+/// ```
+/// Example 2:
+///
+/// ```no_run
+/// let builder = gtk::Builder::new_from_resource("/org/gnome/App/ui/widget.ui");
+/// get_widget!(builder, gtk::Label, @my_label).set_text("Salut world");
+/// ```
 #[macro_export]
 macro_rules! get_widget {
     ($builder:expr, $wtype:ty, @$name:ident) => {{
@@ -9,6 +25,13 @@ macro_rules! get_widget {
     };
 }
 
+
+/// Example:
+/// ```no_run
+/// spawn!(async {
+///     something.await;
+/// });
+/// ```
 #[macro_export]
 macro_rules! spawn {
     ($future:expr) => {
@@ -26,6 +49,20 @@ macro_rules! send {
     };
 }
 
+
+/// Example:
+/// ```no_run
+/// let widget = get_widget!(builder, gtk::Window, widget);
+/// let actions = gio::SimpleActionGroup::new();
+/// widget.insert_action_group("export", Some(&actions));
+/// action!(
+///     actions,
+///     "do",
+///     move |action, _| {
+///         // do something
+///     },
+///);
+/// ```
 #[macro_export]
 macro_rules! action {
     ($actions_group:expr, $name:expr, $callback:expr) => {
@@ -40,6 +77,19 @@ macro_rules! action {
     };
 }
 
+/// Example:
+/// ```no_run
+/// let actions = gio::SimpleActionGroup::new();
+/// let is_dark_mode = false;
+/// stateful_action!(actions, "dark-mode", is_dark_mode, move |action, _| {
+///     let state = action.get_state().unwrap();
+///     let action_state: bool = state.get().unwrap();
+///     let is_dark_mode = !action_state;
+///     action.set_state(&is_dark_mode.to_variant());
+///
+///     // Store the state using gsettings for example
+/// });
+/// ```
 #[macro_export]
 macro_rules! stateful_action {
     ($actions_group:expr, $name:expr, $state:expr, $callback:expr) => {
@@ -55,6 +105,19 @@ macro_rules! stateful_action {
 }
 
 
+/// Example:
+/// ```no_run
+/// let actions = gio::SimpleActionGroup::new();
+/// widget.insert_action_group("export", Some(&actions));
+/// action!(
+///     actions,
+///     "do",
+///     move |action, _| {
+///         // do something
+///     },
+///);
+/// get_action!(actions, @delete).set_enabled(false);
+/// ```
 #[macro_export]
 macro_rules! get_action {
     ($actions:expr, @$name:ident) => {{