Fix some clippy errors that didn't appear on my host version of clippy.

src/parser/line_break.rs

@@ -21,7 +21,7 @@ pub(crate) fn line_break<'b, 'g, 'r, 's>(
     input: OrgSource<'s>,
 ) -> Res<OrgSource<'s>, LineBreak<'s>> {
     let (remaining, _) = pre(context, input)?;
-    let (remaining, _) = tag(r#"\\"#)(remaining)?;
+    let (remaining, _) = tag(r"\\")(remaining)?;
     let (remaining, _) = recognize(many0(one_of(" \t")))(remaining)?;
     let (remaining, _) = line_ending(remaining)?;
     let source = get_consumed(input, remaining);