feat(analysis/special_functions/trigonometric): periodicity of sine, cosine (#7107)
feat(analysis/special_functions/trigonometric): periodicity of sine, cosine (#7107)

Previously we only had `sin (x + 2 * π) = sin x` and `cos (x + 2 * π) = cos x`. I extend those results to cover shifts by any integer multiple of `2 * π`, not just `2 * π`. I also provide corresponding `sub` lemmas. 





leanprover-community/mathlib,leanprover-community/mathlib