add to doc: guidance for choosing polynomial (#213)#219

dlfivefifty merged 3 commits intoJuliaApproximation:mainJuliaApproximation/ClassicalOrthogonalPolynomials.jl:mainfrom

onzerem:on/documentationonzerem/ClassicalOrthogonalPolynomials.jl:on/documentationCopy head branch name to clipboard