Some details for Castalia statistics file

Before XE7 Castalia used to be standalone expert thus I suppose here should be some grounding

Delphi.gitignore

@@ -53,5 +53,5 @@
 __history/
 *.~*
 
-# Castalia statistics file
+# Castalia statistics file (since XE7 Castalia is distributed with Delphi)
 *.stat