Support text markup at the start of a regular link description.

src/parser/radio_link.rs

@@ -108,7 +108,7 @@ pub(crate) fn radio_target<'b, 'g, 'r, 's>(
             class: ExitClass::Gamma,
             exit_matcher: &radio_target_end,
         }),
-        ContextElement::StartRadioTarget(remaining),
+        ContextElement::StartTextSection(remaining),
     ];
     let parser_context = context.with_additional_node(&contexts[0]);
     let parser_context = parser_context.with_additional_node(&contexts[1]);