CI: autofix rust code.

src/parser/keyword.rs

@@ -19,7 +19,7 @@ use crate::parser::Keyword;
 
 #[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
 pub fn keyword<'r, 's>(
-    context: Context<'r, 's>,
+    _context: Context<'r, 's>,
     input: OrgSource<'s>,
 ) -> Res<OrgSource<'s>, Keyword<'s>> {
     start_of_line(input)?;