patch 8.2.0774: t_TI and t_TE are output when using 'visualbell'

Problem:    t_TI and t_TE are output when using 'visualbell'. (Dominique
            Pelle)
Solution:   Do not change the terminal mode for a short sleep.  Do not output
            t_TI and t_TE when switching to/from TMODE_SLEEP. Make tmode an
            enum.
diff --git a/src/globals.h b/src/globals.h
index 11e06be..60c3c66 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -1171,7 +1171,7 @@
 EXTERN int	term_console INIT(= FALSE); // set to TRUE when console used
 #endif
 EXTERN int	termcap_active INIT(= FALSE);	// set by starttermcap()
-EXTERN int	cur_tmode INIT(= TMODE_COOK);	// input terminal mode
+EXTERN tmode_T	cur_tmode INIT(= TMODE_COOK);	// input terminal mode
 EXTERN int	bangredo INIT(= FALSE);	    // set to TRUE with ! command
 EXTERN int	searchcmdlen;		    // length of previous search cmd
 #ifdef FEAT_SYN_HL