Could link html docs to their documentation files on github

[mrjbq7]

From a request on Discord, we could add a link to the documentation source code on the docs.factorcode.org help files:

diff --git a/basis/help/html/html.factor b/basis/help/html/html.factor
index aba0d61f95..0bb2768e0d 100644
--- a/basis/help/html/html.factor
+++ b/basis/help/html/html.factor
@@ -1,14 +1,14 @@
 ! Copyright (C) 2008, 2011 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: accessors arrays ascii assocs colors
-combinators.short-circuit debugger formatting help help.home
-help.topics help.vocabs html html.streams io.directories
-io.encodings.ascii io.encodings.binary io.encodings.utf8
-io.files io.files.temp io.pathnames kernel make math math.parser
-namespaces regexp sequences sequences.deep serialize sets
-sorting splitting strings system tools.completion vocabs
-vocabs.hierarchy words xml.data xml.syntax xml.traversal
-xml.writer ;
+combinators.short-circuit debugger definitions formatting help
+help.home help.topics help.vocabs html html.streams
+io.directories io.encodings.ascii io.encodings.binary
+io.encodings.utf8 io.files io.files.temp io.pathnames kernel
+make math math.parser namespaces regexp sequences sequences.deep
+serialize sets sorting splitting strings system tools.completion
+vocabs vocabs.hierarchy vocabs.loader words xml.data xml.syntax
+xml.traversal xml.writer ;
 FROM: io.encodings.ascii => ascii ;
 FROM: ascii => ascii? ;
 IN: help.html
@@ -62,12 +62,14 @@ M: f topic>filename* drop \ f topic>filename* ;
 
 M: topic url-of topic>filename ;
 
-M: pathname url-of
-    string>> "resource:" ?head [
+M: string url-of
+    "resource:" ?head [
         "https://github.com/factor/factor/blob/master/"
         prepend
     ] [ drop f ] if ;
 
+M: pathname url-of string>> url-of ;
+
 : help-stylesheet ( stylesheet -- xml )
     "vocab:help/html/stylesheet.css" ascii file-contents
     swap "\n" glue [XML <style><-></style> XML] ;
@@ -107,8 +109,24 @@ M: pathname url-of
         </nav>
      XML] ;
 
-: help-footer ( -- xml )
-    version-info "\n" split1 drop
+GENERIC: topic-docs-path ( topic -- docs-path )
+
+M: object topic-docs-path
+    vocab-name ".private" ?tail drop vocab-docs-path ;
+
+M: word topic-docs-path
+    dup "help-loc" word-prop
+    [ nip first ] [ vocabulary>> topic-docs-path ] if* ;
+
+: topic-link ( topic -- xml/f ) 
+    topic-docs-path [
+        [ url-of ] keep [XML
+            <a style="font-family: monospace;" href=<->><-></a>
+        XML]
+    ] [ f ] if* ;
+
+: help-footer ( topic -- xml )
+    [ version-info "\n" split1 drop ] dip topic-link
     [XML
         <footer>
         <p>
@@ -120,6 +138,7 @@ M: pathname url-of
         for more information.
         </p>
         <p><-></p>
+        <->
         </footer>
     XML] ;
 
@@ -250,9 +269,10 @@ M: pathname url-of
         [ print-topic ] with-html-writer
         css-styles-to-classes cache-images
         "resource:extra/websites/factorcode/favicon.ico" dup file-name ?copy-file
-        [ help-stylesheet help-meta prepend help-nav ] dip help-footer
-        [XML <-><div class="page"><-><-></div> XML]
-    ] bi simple-page ;
+        [ help-stylesheet help-meta prepend help-nav ] dip
+    ]
+    [ help-footer ] tri
+    [XML <-><div class="page"><-><-></div> XML] simple-page ;
 
 : generate-help-file ( topic -- )
     dup topic>filename utf8 [ help>html write-xml ] with-file-writer ;