Use non-directory-style ref target for camera examples

Author: pushfoo

doc/example_code/how_to_examples/index.rst

@@ -404,7 +404,7 @@ Backgrounds
 
    :ref:`background_parallax`
 
-.. _examples_cameras:
+.. _camera_examples:
 
 Cameras
 ^^^^^^^

doc/programming_guide/sprites/spritelists.rst

@@ -86,5 +86,5 @@ Viewports, Cameras, and Screens
 Intermediate users can move past the limitations of :py:class:`arcade.Window`
 with the following classes:
 
-* :py:class:`arcade.Camera` (:ref:`examples <examples_cameras>`) to control which part of game space is drawn
+* :py:class:`arcade.Camera` (:ref:`examples <camera_examples>`) to control which part of game space is drawn
 * :py:class:`arcade.View` (:ref:`examples <view_examples>`) for start, end, and menu screens