Fix making of "sources.html"

Uses same template as synopsis, maybe this shoudl be generalised a bit

doc/synopsis/.gitignore

@@ -1,6 +0,0 @@
-index.txt
-index.html
-api-examples-*.txt
-api-examples.gfs
-categories-imagemap.html
-categories.png

doc/synopsis/intro.txt

@@ -68,7 +68,7 @@ Other relevant documents:
   and the authors of each grammar
 - [The Resource Grammar Library coverage map http://www.postcrashgames.com/gf_world/]
 - [RGL Documentation and Publications ../rgl-publications.html]: links to publications and other documentation
-- [More modules gfdoc/sources.html]: extra modules, dictionaries, and
+- [More modules ../gfdoc/sources.html]: extra modules, dictionaries, and
   the internals of the resource grammar
 - [Internal abstract syntax ../absfuns.html]: synopsis of internal
 abstract functions and their Universal Dependency labels

doc/synopsis/quicklinks.js

@@ -115,4 +115,10 @@ function quicklinks () {
   )
 }
 
-document.getElementById('quicklinks').appendChild(quicklinks())
+appendChildren(
+  document.getElementById('quicklinks'),
+  [
+    node('h5', '', 'Quick links'),
+    quicklinks()
+  ]
+)

doc/synopsis/template.html

@@ -32,7 +32,6 @@ $endfor$
 <div class="row">
 
   <nav class="col-md-3 col-xl-2 d-none d-md-block sidebar" id="quicklinks">
-    <h5>Quick links</h5>
     <!-- filled dynamically via quicklinks.js -->
   </nav>