I do not know why but using
```@autodocs
Modules = [MyPackage]
where MyPackage is the the module in which (::LinearAlgebra.UniformScaling)(::Integer) is throws no error.
Here is the case. The content of the module is
module MyPackage
using LinearAlgebra
"""
(I::UniformScaling)(n::Integer)
Some explanation.
"""
(I::UniformScaling)(n::Integer) = Diagonal(fill(I.λ, n))
end # module
and the content of index.md is
# MyPackage.jl
```@autodocs
Modules = [MyPackage]
The resulting output is
