docs: Add brief descriptions to all functions

This ensures all of these functions are picked up by g-ir-scanner.

lib/wp/device.c

@@ -564,6 +564,8 @@ wp_spa_device_class_init (WpSpaDeviceClass * klass)
 }
 
 /*!
+ * \brief Constructs an SPA Device object from an existing device handle.
+ *
  * \ingroup wpspadevice
  * \param core the wireplumber core
  * \param spa_device_handle the spa device handle
@@ -622,6 +624,8 @@ wp_spa_device_new_from_spa_factory (WpCore * core,
 }
 
 /*!
+ * \brief Gets the properties of this device.
+ *
  * \ingroup wpspadevice
  * \param self the spa device
  * \returns (transfer full): the device properties
@@ -634,6 +638,8 @@ wp_spa_device_get_properties (WpSpaDevice * self)
 }
 
 /*!
+ * \brief Gets one of the objects managed by this device.
+ *
  * \ingroup wpspadevice
  * \param self the spa device
  * \param id the (device-internal) id of the object to get
@@ -650,6 +656,8 @@ wp_spa_device_get_managed_object (WpSpaDevice * self, guint id)
 }
 
 /*!
+ * \brief Stores or removes a managed object into/from a device.
+ *
  * \ingroup wpspadevice
  * \param self the spa device
  * \param id the (device-internal) id of the object