Add CLIP_SPACE_FAR built-in description to spatial shaders

Author: Chaosus

tutorials/shaders/shader_reference/spatial_shader.rst

@@ -185,6 +185,10 @@ shader, this value can be used as desired.
 |                                        | (this is ``true`` in the Compatibility renderer,       |
 |                                        | ``false`` in Forward+ and Forward Mobile).             |
 +----------------------------------------+--------------------------------------------------------+
+| in bool **CLIP_SPACE_FAR**             | End of a clip space range.                             |
+|                                        | When using a Vulkan renderer, it's ``0``.              |
+|                                        | On compatibility renderer, it's ``-1``.                |
++----------------------------------------+--------------------------------------------------------+
 | in int **INSTANCE_ID**                 | Instance ID for instancing.                            |
 +----------------------------------------+--------------------------------------------------------+
 | in vec4 **INSTANCE_CUSTOM**            | Instance custom data (for particles, mostly).          |
@@ -288,6 +292,10 @@ these properties, and if you don't write to them, Godot will optimize away the c
 | in bool **OUTPUT_IS_SRGB**             | ``true`` when output is in sRGB color space (this is ``true`` in the Compatibility renderer,     |
 |                                        | ``false`` in Forward+ and Forward Mobile).                                                       |
 +----------------------------------------+--------------------------------------------------------------------------------------------------+
+| in bool **CLIP_SPACE_FAR**             | End of a clip space range.                                                                       |
+|                                        | When using a Vulkan renderer, it's ``0``.                                                        |
+|                                        | On compatibility renderer, it's ``-1``.                                                          |
++----------------------------------------+--------------------------------------------------------------------------------------------------+
 | in mat4 **MODEL_MATRIX**               | Model/local space to world space transform.                                                      |
 +----------------------------------------+--------------------------------------------------------------------------------------------------+
 | in mat3 **MODEL_NORMAL_MATRIX**        |                                                                                                  |
@@ -488,6 +496,10 @@ If you want the lights to add together, add the light contribution to ``DIFFUSE_
 |                                   | This is ``true`` in the Compatibility renderer,                        |
 |                                   | ``false`` in Forward+ and Forward Mobile.                              |
 +-----------------------------------+------------------------------------------------------------------------+
+| in bool **CLIP_SPACE_FAR**        | End of a clip space range.                                             |
+|                                   | When using a Vulkan renderer, it's ``0``.                              |
+|                                   | On compatibility renderer, it's ``-1``.                                |
++-----------------------------------+------------------------------------------------------------------------+
 | out vec3 **DIFFUSE_LIGHT**        | Diffuse light result.                                                  |
 +-----------------------------------+------------------------------------------------------------------------+
 | out vec3 **SPECULAR_LIGHT**       | Specular light result.                                                 |