doc: Fix host forwarding monitor command documentation

Commit f3546deb replaced host_net_redir by hostfwd_add,
hostfwd_remove, but neglected to update documentation.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/qemu-monitor.hx b/qemu-monitor.hx
index 5ea5748..21aeb6b 100644
--- a/qemu-monitor.hx
+++ b/qemu-monitor.hx
@@ -953,7 +953,14 @@
         .help       = "redirect TCP or UDP connections from host to guest (requires -net user)",
         .mhandler.cmd = net_slirp_hostfwd_add,
     },
+#endif
+STEXI
+@item hostfwd_add
+@findex hostfwd_add
+Redirect TCP or UDP connections from host to guest (requires -net user).
+ETEXI
 
+#ifdef CONFIG_SLIRP
     {
         .name       = "hostfwd_remove",
         .args_type  = "arg1:s,arg2:s?,arg3:s?",
@@ -964,9 +971,9 @@
 
 #endif
 STEXI
-@item host_net_redir
-@findex host_net_redir
-Redirect TCP or UDP connections from host to guest (requires -net user).
+@item hostfwd_remove
+@findex hostfwd_remove
+Remove host-to-guest TCP or UDP redirection.
 ETEXI
 
     {