docs: tell cljdoc toc about md->adoc (#66)

Author: lread

doc/cljdoc.edn

@@ -1,6 +1,6 @@
 {:cljdoc.doc/tree
- [["Readme" {:file "README.md"}]
-  ["Changelog" {:file "CHANGELOG.md"}]
+ [["Readme" {:file "README.adoc"}]
+  ["Changelog" {:file "CHANGELOG.adoc"}]
   ["User Guide" {:file "doc/01-user-guide.adoc"}]
   ["Developer Guide" {:file "doc/02-developer-guide.adoc"}]
   ["Maintainer Guide" {:file "doc/03-maintainer-guide.adoc"}]]}