Incorporate Slang User Guide into readthedocs site (#87)

This replaces the external links to the Slang User Guide in the readthedocs index file with references to the internal copy in the submodule.

Author: aidanfnv

docs/conf.py

@@ -105,6 +105,3 @@ def setup(app):
         "color-api-background": "#1e1e1e",
     },
 }
-
-# Use default Furo sidebar configuration - remove custom sidebar
-# html_sidebars = {}  # Let Furo use its defaults

docs/index.rst

@@ -6,7 +6,7 @@ Slang Documentation
    :maxdepth: 1
    :titlesonly:
 
-   User Guide <https://shader-slang.org/slang/user-guide/>
+   User Guide <external/slang/docs/user-guide/index>
    Standard Modules Reference <external/stdlib-reference/index>
    Language Spec <https://github.com/shader-slang/spec>
    SlangPy User Guide <external/slangpy/docs/index.rst>
@@ -19,9 +19,9 @@ Slang Documentation
    :maxdepth: 1
    :titlesonly:
 
-   SPIR-V Specific Functionalities <https://shader-slang.org/slang/user-guide/spirv-target-specific.html>
-   Metal Specific Functionalities <https://shader-slang.org/slang/user-guide/spirv-target-specific.html>
-   WGSL Specific Functionalities <https://shader-slang.org/slang/user-guide/spirv-target-specific.html>
+   SPIR-V Specific Functionalities <external/slang/docs/user-guide/a2-01-spirv-target-specific>
+   Metal Specific Functionalities <external/slang/docs/user-guide/a2-02-metal-target-specific>
+   WGSL Specific Functionalities <external/slang/docs/user-guide/a2-03-wgsl-target-specific>
 
 .. toctree::
    :caption: Tutorials
@@ -30,7 +30,7 @@ Slang Documentation
 
    Write Your First Slang Shader <first-slang-shader>
    Using the Compilation API <compilation-api>
-   Using the Reflection API <https://shader-slang.org/slang/user-guide/reflection.html>
+   Using the Reflection API <external/slang/docs/user-guide/09-reflection>
    Shader Cursors: Advanced Usage of the Reflection API <shader-cursors>
    Understanding Slang Generics <understanding-generics>
    Migrating from HLSL to Slang <coming-from-hlsl>