Add sincospi(x)

[jmert]

Added to Base in JuliaLang/julia#35816

The five tests I added cover the methods I see on Julia v1.6 master:

julia> methods(sincospi)
# 5 methods for generic function "sincospi":
[1] sincospi(x::T) where T<:AbstractFloat in Base.Math at special/trig.jl:871
[2] sincospi(x::T) where T<:Rational in Base.Math at special/trig.jl:903
[3] sincospi(x::Integer) in Base.Math at special/trig.jl:935
[4] sincospi(x::Real) in Base.Math at special/trig.jl:938
[5] sincospi(z::Complex{T}) where T in Base.Math at special/trig.jl:1009

[simeonschaub]

👍 Looks good to me!

[martinholters]

LGTM. Feel free to also bump the version in Project.toml and we'll tag immediately after merging.

[jmert]

Feel free to also bump the version in Project.toml and we'll tag immediately after merging.

Done.

[martinholters]

Thanks for the contribution! .. and welcome!