remove unused import

Author: CAD97

src/parse/macros/cfg_match.rs

@@ -4,7 +4,6 @@ use rustc_ast::ast;
 use rustc_ast::token::{Delimiter, TokenKind};
 use rustc_parse::exp;
 use rustc_parse::parser::ForceCollect;
-use rustc_span::symbol::kw;
 
 use crate::parse::macros::build_stream_parser;
 use crate::parse::session::ParseSess;