Parser: added the support file annotations to grammar.

grammar/src/toplevel.grm

@@ -16,7 +16,15 @@ script
   ;
 
 preamble
-  : packageHeader? import*
+  : fileAnnotations? packageHeader? import*
+  ;
+
+fileAnnotations
+  : fileAnnotation*
+  ;
+
+fileAnnotation
+  : "[" "file" ":" annotationEntry+ "]"
   ;
 
 packageHeader
@@ -54,4 +62,4 @@ See [Packages](packages.html)
 [undocumented]
 typedef
   : modifiers "type" SimpleName (typeParameters typeConstraints)? "=" type
-  ;
+  ;