docs: fix all broken cross-reference links

docs/concepts/shader-basics.md

@@ -79,7 +79,7 @@ Data flows between the vertex and fragment stages through a shared struct. The s
 
 The vertex shader produces a struct containing a `@builtin(position)` output plus any number of `@location` interpolants. The rasterizer takes these outputs, assembles [[primitives]](GLOSSARY.md#primitive), and for every pixel inside the triangle computes [[barycentric coordinates]](GLOSSARY.md#barycentric-coordinates) and blends all `@location` fields. The fragment shader receives the fully interpolated struct and outputs a `vec4<f32>` color at `@location(0)`, which maps to the [[pipeline]](GLOSSARY.md#pipeline)'s color attachment target.
 
-For a complete line-by-line walkthrough of our rainbow triangle shader, see [Section 4](01-rainbow-triangle.md#section-4-writing-the-shaders).
+For a complete line-by-line walkthrough of our rainbow triangle shader, see [Section 4](01-rainbow-triangle.md#s4-writing-the-shaders).
 
 ## WGSL Source Embedding