Don't error for missing docs in docs build

Author: mtfishman

docs/make.jl

@@ -13,6 +13,7 @@ makedocs(;
     canonical="https://ITensor.github.io/ITensors.jl", edit_link="main", assets=String[]
   ),
   pages=["Home" => "index.md"],
+  warnonly=Documenter.except(:missing_docs),
 )
 
 deploydocs(; repo="github.com/ITensor/ITensors.jl", devbranch="main", push_preview=true)

src/SiteTypes/sitetype.jl

@@ -1,6 +1,9 @@
 using ChainRulesCore: @ignore_derivatives
 using ..ITensors:
-  ITensors, Index, ITensor, itensor, addtags, dag, onehot, prime, product, swapprime, tags
+  ITensors, Index, ITensor, itensor, addtags, dag, onehot, prime, swapprime, tags
+
+# TODO: Need to define.
+# using ..ITensors: product
 
 @eval struct SiteType{T}
   (f::Type{<:SiteType})() = $(Expr(:new, :f))