Add klish extension yang file

Makefile.am

@@ -24,10 +24,8 @@ EXTRA_DIST = \
 	src/Makefile.am \
 	LICENCE \
 	README.md \
-	xml
+	xml \
+	yang
 
 include $(top_srcdir)/bin/Makefile.am
 include $(top_srcdir)/src/Makefile.am
-
-#xmldir = $(sysconfdir)/klish
-#dist_xml_DATA = xml/sysrepo.xml

yang/klish.yang

@@ -0,0 +1,10 @@
+module klish {
+  namespace "http://klish.libcode.org/yang/klish";
+  prefix "klish";
+  description "Klish extensions. The klish-plugin-sysrepo can use it.";
+
+  extension completion {
+    argument "xpath";
+    description "XPath for autocompletion.";
+  }
+}