fix(docs): Add repo key word to allow local builds

When one has no `origin` remote and tries to build locally the build
fails if this is not set.

Author: kunzaatko

docs/make.jl

@@ -2,6 +2,7 @@ using Documenter, AbstractFFTs
 
 makedocs(
     modules = [AbstractFFTs],
+    repo="https://github.com/JuliaMath/AbstractFFTs.jl/blob/{commit}{path}#{line}",
     sitename = "AbstractFFTs.jl",
     pages = Any[
         "Home" => "index.md",