add default derive to buffer unit components (#143)

src/cosmic_edit.rs

@@ -25,7 +25,7 @@ impl Default for CosmicTextAlign {
 
 /// Tag component to disable writing to a [`CosmicBuffer`]
 // TODO: Code example
-#[derive(Component)]
+#[derive(Component, Default)]
 pub struct ReadOnly; // tag component
 
 /// Internal value used to decide what section of a [`Buffer`] to render

src/user_select.rs

@@ -11,7 +11,7 @@ impl Plugin for UserSelectPlugin {
 
 /// Tag component to disable user selection
 /// Like CSS `user-select: none` https://developer.mozilla.org/en-US/docs/Web/CSS/user-select
-#[derive(Component)]
+#[derive(Component, Default)]
 pub struct UserSelectNone;
 
 fn clear_selection(mut q: Query<&mut CosmicEditor, With<UserSelectNone>>) {