[internet.synop] Rename host_not_found_try_again enumerator

Fixes NB GB-20 (PDTS)

Author: jwakely

src/internetprotocol.tex

@@ -20,7 +20,7 @@
 
   enum class resolver_errc {
     host_not_found = @\textit{an \impldef{value of the \tcode{host_not_found} error code} non-zero value}@, // \textit{EAI_NONAME}
-    host_not_found_try_again = @\textit{an \impldef{value of the \tcode{host_not_found_try_again} error code} non-zero value}@, // \textit{EAI_AGAIN}
+    try_again = @\textit{an \impldef{value of the \tcode{try_again} error code} non-zero value}@, // \textit{EAI_AGAIN}
     service_not_found = @\textit{an \impldef{value of the \tcode{service_not_found} error code} non-zero value}@ // \textit{EAI_SERVICE}
   };