fix xrefs

docs/modules/ROOT/pages/jme3/matrix.adoc

@@ -1,10 +1,7 @@
 = Matrix
 :author:
 :revnumber:
-:revdate: 2016/03/17 20:48
-:relfileprefix: ../
-:imagesdir: ..
-ifdef::env-github,env-browser[:outfilesuffix: .adoc]
+:revdate: 2020/07/15