Fix cargo doc warnings

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

src/context.rs

@@ -109,13 +109,13 @@ pub trait UsbContext: Clone + Sized + Send + Sync {
     /// [Hotplug::device_arrived] method is called when a new device is added to
     /// the bus, and [Hotplug::device_left] is called when it is removed.
     ///
-    /// Devices can optionally be filtered by vendor ([vendor_id]) and device id
-    /// ([device_id]). If [enumerate] is `true`, then devices that are already
-    /// connected will cause your callback's `device_arrived()` method to be
-    /// called for them.
+    /// Devices can optionally be filtered by `vendor_id` and `device_id`. If
+    /// `enumerate` is `true`, then devices that are already connected will
+    /// cause your callback's `device_arrived()` method to be called for them.
     ///
     /// The callback will remain registered until the returned [Registration] is
-    /// dropped, which can be done explicitly with [hotplug_unregister_callback].
+    /// dropped, which can be done explicitly with
+    /// [hotplug_unregister_callback][Self::hotplug_unregister_callback()].
     #[must_use = "USB hotplug callbacks will be deregistered if the registration is dropped"]
     fn hotplug_register_callback(
         &self,