textio/txInput.c non-void function does not return a value

This function is related to libreadline rl_pre_input_hook callback
which is invoked as (not making use of any function return value):

readline.c:    (*rl_pre_input_hook) ();

The general prototype for this function is:

rltypedefs.h:typedef int rl_hook_func_t PARAMS((void));

So the resolution is to provide a known value as the return value, which
resolves the concern.

SonarCloud
textio/txInput.c:550 non-void function does not return a value
https://sonarcloud.io/project/issues?open=AZJB17NwNGfDNup0Rj5G&id=dlmiles_magic

textio/txInput.c

@@ -547,6 +547,7 @@ TxPrefix(void)
     if (_rl_prefix != NULL)
 	rl_insert_text(_rl_prefix);
     rl_redisplay();
+    return 0;
 }
 
 /*