fix types in index

docs/src/api.md

@@ -23,16 +23,16 @@ QuadGK.alloc_segbuf
 For more specialized applications, you may wish to construct your own Gauss or Gauss–Kronrod quadrature rules, as described in [Gauss and Gauss–Kronrod quadrature rules](@ref).   To compute rules for $\int_{-1}^{+1} f(x) dx$ and $\int_a^b f(x) dx$ (unweighted integrals), use:
 
 ```@docs
-QuadGK.gauss(::Type, ::Integer)
-QuadGK.kronrod(::Type, ::Integer)
+QuadGK.gauss(::Type{<:AbstractFloat}, ::Integer)
+QuadGK.kronrod(::Type{<:AbstractFloat}, ::Integer)
 ```
 
 More generally, to compute rules for $\int_a^b w(x) f(x) dx$ (weighted integrals, as described in [Gaussian quadrature and arbitrary weight functions](@ref)), use the following methods if you know the [Jacobi matrix](https://en.wikipedia.org/wiki/Jacobi_operator) for the orthogonal
 polynomials associated with your weight function:
 
 ```@docs
-QuadGK.gauss(::AbstractMatrix, ::Real)
-QuadGK.kronrod(::AbstractMatrix, ::Integer, ::Real)
+QuadGK.gauss(::AbstractMatrix{<:Real}, ::Real)
+QuadGK.kronrod(::AbstractMatrix{<:Real}, ::Integer, ::Real)
 QuadGK.HollowSymTridiagonal
 ```