The new correction avoids washed out areas near the shadow terminator,
preserving more detail from normal and bump maps.
It implements the method from the paper "A Microfacet-Based Shadowing
Function to Solve the Bump Terminator Problem" by Alejandro Conty Estevez,
Pascal Lecocq, and Clifford Stein.
Pull Request: https://projects.blender.org/blender/blender/pulls/135380
5e2afb3f6f