Fix warnings.

src/parser/plain_list.rs

@@ -1,7 +1,7 @@
 use super::greater_element::PlainList;
 use super::greater_element::PlainListItem;
 use super::parser_with_context::parser_with_context;
-use super::util::maybe_consume_trailing_whitespace_if_not_exiting;
+
 use super::util::non_whitespace_character;
 use super::Context;
 use crate::error::CustomError;