docs(wayland): add comments for each fields added

Author: tymmesyde

src/platform_impl/linux/wayland/seat/mod.rs

@@ -67,6 +67,7 @@ pub struct WinitSeatState {
     /// Whether we have pending modifiers.
     modifiers_pending: bool,
 
+    /// The current data device.
     data_device: Option<DataDevice>,
 }
 

src/platform_impl/linux/wayland/state.rs

@@ -56,7 +56,10 @@ pub struct WinitState {
     /// The seat state responsible for all sorts of input.
     pub seat_state: SeatState,
 
+    // The state of the data device manager.
     pub data_device_manager_state: DataDeviceManagerState,
+
+    // The active drag and drop offers.
     pub dnd_offers: AHashMap<ObjectId, DndOfferState>,
 
     /// The shm for software buffers, such as cursors.