Improve lifetimes for get_property_numeric.

src/compare/util.rs

@@ -243,10 +243,10 @@ pub(crate) fn get_property_boolean<'b, 's, 'x>(
 pub(crate) fn get_property_numeric<'b, 's, 'x, N: FromStr>(
     emacs: &'b Token<'s>,
     key: &'x str,
-) -> Result<Option<N>, Box<dyn std::error::Error>>
+) -> Result<Option<N>, Box<dyn std::error::Error + 's>>
 where
     <N as FromStr>::Err: std::error::Error,
-    <N as FromStr>::Err: 'static,
+    <N as FromStr>::Err: 's,
 {
     let foo = get_property(emacs, key)?
         .map(Token::as_atom)