Footnote definitions are parsing on their own.

src/parser/plain_list.rs

@@ -4,6 +4,7 @@ use super::error::Res;
 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;
 use super::util::non_whitespace_character;
 use super::Context;
 use crate::parser::element::element;
@@ -49,6 +50,9 @@ pub fn plain_list<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s s
             Ok(_) | Err(_) => break,
         };
     }
+
+    let (remaining, _trailing_ws) = maybe_consume_trailing_whitespace(context, remaining)?;
+
     let source = get_consumed(input, remaining);
     Ok((remaining, PlainList { source, children }))
 }