Replace 'hook' and 'noisy' flags in functions downstream of send_text() with !(stxt_flags & STXT_QUIET)

This is in preparation for consolidating the various send_text() options into one set of consistent flags.

include/irc.h

@@ -165,6 +165,10 @@ extern char	thing_star[4];
 #define MAX(a,b) ((a > b) ? (a) : (b))
 #endif
 
+/* send_text flag values */
+#define STXT_NOTICE 0x0001U
+#define STXT_QUIET  0x0002U
+
 /* This section is for keeping track internally
  * the CVS revision info of the running client.
  * Since so many people are using CVS versions