Add procedure to get the uri of a particular doc

My thinking is that we can generate the URIs for every doc,
then use that to wire up the logic for the routing table

guile-docs/docs.scm

@@ -1,11 +1,13 @@
 (define-module (guile-docs docs)
   #:use-module (srfi srfi-9)
+  #:use-module (web uri)
   #:export (make-doc
             doc?
             doc-module
             doc-symbol
             doc-documentation
-            docs-in-module))
+            docs-in-module
+            document-uri))
 
 (define-record-type <doc>
   (make-doc module symbol documentation)
@@ -14,6 +16,15 @@
   (symbol doc-symbol)
   (documentation doc-documentation))
 
+(define (document-uri doc)
+  "Returns the URI for the provided <doc> argument"
+  (when (doc? doc)
+    (let ((symbol-list (append (doc-module doc)
+                               (list (doc-symbol doc)))))
+      (build-uri 'guiledoc
+                 #:path (string-join (map (lambda (x) (symbol->string x))
+                                          symbol-list)
+                                     "/")))))
 
 (define (docs-in-module module)
   "Returns a list of <doc> for each symbol in module mod"