Don't define an interactive method for any Documenter

Since Documenter subtypes can have extra fields now, it isn't safe.

src/plugins/documenter.jl

@@ -115,9 +115,3 @@ function Base.show(io::IO, p::Documenter)
     print(io, "$spc→ $n gitignore entrie$s")
     n > 0 && print(io, ": $(join(map(g -> "\"$g\"", p.gitignore), ", "))")
 end
-
-function interactive(T::Type{<:Documenter})
-    name = string(nameof(T))
-    print("$name: Enter any Documenter asset files (separated by spaces) []: ")
-    return T(; assets=string.(split(readline())))
-end

src/plugins/githubpages.jl

@@ -61,3 +61,8 @@ function gen_plugin(p::GitHubPages, t::Template, pkg_name::AbstractString)
     end
     return ["docs/"]
 end
+
+function interactive(::Type{GitHubPages})
+    print("GitHubPages: Enter any Documenter asset files (separated by spaces) []: ")
+    return GitHubPages(; assets=string.(split(readline())))
+end