Add graph-typed.scrbl to documentation.

scribblings/dds.scrbl

@@ -25,3 +25,4 @@ dds currently includes the following modules:
 @table-of-contents[]
 
 @include-section["utils.scrbl"]
+@include-section["graph-typed.scrbl"]

scribblings/graph-typed.scrbl

@@ -0,0 +1,19 @@
+#lang scribble/manual
+
+@title[#:tag "graph-typed"]{dds/graph-typed: Incomplete Typed Interface to graph}
+
+@defmodule[dds/graph-typed]
+
+@bold{DISCLAIMER:} This is @bold{not} a complete typed interface to Stephen
+Chang's @hyperlink["https://docs.racket-lang.org/graph/index.html"]{graph
+library}.  Read on for more details.
+
+Stephen Chang's
+@hyperlink["https://docs.racket-lang.org/graph/index.html"]{graph library} is
+used in dds to represent different kinds of graphs (state graphs, interaction
+graphs, graphs of interaction processes, etc.).  This module adds types to the
+functions which are used in dds.  These types do not necessarily capture the
+signatures of the functions entirely, and are mainly meant for internal use.
+I may eventually consider contributing something similar to Stephen Chang's
+library, but it would have to be a more polished product than this module is at
+the moment.