Fix1 (analogue of Base.Fix2)

[stevengj]

@Tamas_Papp

Would it make sense to introduce a Fix1 that does the same, except for fixing the first argument?

Note that this is already planned. See e.g. replace `equalto` and `occursin` with curried `isequal`, `==`, and `in` by JeffBezanson · Pull Request #26436 · JuliaLang/julia · GitHub