LibJS: Keep track of file names, lines and columns inside the AST

Author: https://github.com/boricj
Commit: 0039ecb189
Pull-request: https://github.com/SerenityOS/serenity/pull/5547
Reviewed-by: https://github.com/alimpfard
Reviewed-by: https://github.com/linusg

Userland/Libraries/LibJS/SourceRange.h

@@ -36,6 +36,7 @@ struct Position {
 };
 
 struct SourceRange {
+    StringView filename;
     Position start;
     Position end;
 };