CI: autofix rust code.

src/parser/export_snippet.rs

@@ -48,7 +48,7 @@ pub fn export_snippet<'r, 's>(
 
 #[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
 fn backend<'r, 's>(
-    context: Context<'r, 's>,
+    _context: Context<'r, 's>,
     input: OrgSource<'s>,
 ) -> Res<OrgSource<'s>, OrgSource<'s>> {
     let (remaining, backend_name) =
@@ -71,7 +71,7 @@ fn contents<'r, 's>(
 
 #[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
 fn export_snippet_end<'r, 's>(
-    context: Context<'r, 's>,
+    _context: Context<'r, 's>,
     input: OrgSource<'s>,
 ) -> Res<OrgSource<'s>, OrgSource<'s>> {
     tag("@@")(input)