mathlib

aedfb56f - feat(geometry/euclidean/angle/unoriented): sine & cosine angle lemmas (#18222)

feat(geometry/euclidean/angle/unoriented): sine & cosine angle lemmas (#18222) add some lemma's about sine and cosine of unoriented angles. Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>