Docs: Tweaks

Remove some more redundant "or NULL" blurbs.

gdk/gdk.c

@@ -330,14 +330,13 @@ gdk_display_open_default (void)
 }
 
 /*< private >
- *
- * gdk_get_startup_notification_id
+ * gdk_get_startup_notification_id:
  *
  * Returns the original value of the DESKTOP_STARTUP_ID environment
  * variable if it was defined and valid, or %NULL otherwise.
  *
  * Returns: (nullable) (transfer none): the original value of the
- *   DESKTOP_STARTUP_ID environment variable, or %NULL.
+ *   DESKTOP_STARTUP_ID environment variable
  */
 const char *
 gdk_get_startup_notification_id (void)

gdk/gdkcursor.c

@@ -340,7 +340,7 @@ gdk_cursor_new_from_name (const char *name,
  * @texture: the texture providing the pixel data
  * @hotspot_x: the horizontal offset of the “hotspot” of the cursor
  * @hotspot_y: the vertical offset of the “hotspot” of the cursor
- * @fallback: (nullable): %NULL or the `GdkCursor` to fall back to when
+ * @fallback: (nullable): the `GdkCursor` to fall back to when
  *   this one cannot be supported
  *
  * Creates a new cursor from a `GdkTexture`.

gdk/gdkdisplay.c

@@ -384,11 +384,11 @@ gdk_display_is_closed  (GdkDisplay  *display)
  * gdk_display_get_event:
  * @display: a `GdkDisplay`
  *
- * Gets the next `GdkEvent` to be processed for @display, fetching events from the
- * windowing system if necessary.
+ * Gets the next `GdkEvent` to be processed for @display,
+ * fetching events from the windowing system if necessary.
  *
- * Returns: (nullable) (transfer full): the next `GdkEvent` to be processed,
- *   or %NULL if no events are pending
+ * Returns: (nullable) (transfer full): the next `GdkEvent`
+ *   to be processed
  */
 GdkEvent *
 gdk_display_get_event (GdkDisplay *display)

gdk/gdkdisplaymanager.c

@@ -323,7 +323,8 @@ gdk_display_manager_get_default_display (GdkDisplayManager *manager)
  * Gets the default `GdkDisplay`.
  *
  * This is a convenience function for:
- * `gdk_display_manager_get_default_display (gdk_display_manager_get ())`.
+ *
+ *     gdk_display_manager_get_default_display (gdk_display_manager_get ())
  *
  * Returns: (nullable) (transfer none): a `GdkDisplay`, or %NULL if
  *   there is no default display

gdk/gdkframeclock.c

@@ -481,11 +481,11 @@ _gdk_frame_clock_begin_frame (GdkFrameClock *frame_clock)
  * for the current frame or a recent frame.
  *
  * The `GdkFrameTimings` object may not yet be complete: see
- * [method@Gdk.FrameTimings.get_complete].
+ * [method@Gdk.FrameTimings.get_complete] and
+ * [method@Gdk.FrameClock.get_history_start].
  *
  * Returns: (nullable) (transfer none): the `GdkFrameTimings` object
- *   for the specified frame, or %NULL if it is not available. See
- *   [method@Gdk.FrameClock.get_history_start].
+ *   for the specified frame, or %NULL if it is not available
  */
 GdkFrameTimings *
 gdk_frame_clock_get_timings (GdkFrameClock *frame_clock,