[AST] Add method to concatenate AstRawStrings

src/parsing/parser.h

Index: src/parsing/parser.h
diff --git a/src/parsing/parser.h b/src/parsing/parser.h
index 81342e34c4783ce6acedabcce7683f8b70857683..069940b760c12a1b2092bff946d4f6432a21be9d 100644
--- a/src/parsing/parser.h
+++ b/src/parsing/parser.h
@@ -291,6 +291,7 @@ class Parser : public ParserBase<Parser> {
                                 ZoneList<const AstRawString*>* names,
                                 bool* ok);
   DoExpression* ParseDoExpression(bool* ok);
+  Property* ParsePrivateFieldReference(Expression* base, bool* ok);
   Expression* ParseYieldStarExpression(bool* ok);
 
   class PatternRewriter final : public AstVisitor<PatternRewriter> {