fix header

docs/modules/tutorials/pages/intermediate/math_for_dummies.adoc

@@ -1,10 +1,6 @@
 = Math For Dummies
-:author:
-:revnumber:
-:revdate: 2016/03/17 20:48
-:relfileprefix: ../
-:imagesdir: ..
-ifdef::env-github,env-browser[:outfilesuffix: .adoc]
+:revnumber: 2.0
+:revdate: 2020/07/13