Make useful DEL in application mode

DEL key has to generate the sequence ^[P in application mode,
because such sequence means delete current character. It implies
that the character sent in keypad mode must be ^? (DEL character).

config.def.h

@@ -200,7 +200,8 @@ static Key key[] = {
 	{ XK_KP_Delete,     ControlMask,    "\033[3;5~",    +1,    0,    0},
 	{ XK_KP_Delete,     ShiftMask,      "\033[2K",      -1,    0,    0},
 	{ XK_KP_Delete,     ShiftMask,      "\033[3;2~",    +1,    0,    0},
-	{ XK_KP_Delete,     XK_ANY_MOD,     "\033[3~",      +1,    0,    0},
+	{ XK_KP_Delete,     XK_ANY_MOD,     "\033[P",       -1,    0,    0},
+	{ XK_KP_Delete,     XK_ANY_MOD,     "\177",         +1,    0,    0},
 	{ XK_KP_Multiply,   XK_ANY_MOD,     "\033Oj",       +2,    0,    0},
 	{ XK_KP_Add,        XK_ANY_MOD,     "\033Ok",       +2,    0,    0},
 	{ XK_KP_Enter,      XK_ANY_MOD,     "\033OM",       +2,    0,    0},
@@ -254,7 +255,8 @@ static Key key[] = {
 	{ XK_Delete,        ControlMask,    "\033[3;5~",    +1,    0,    0},
 	{ XK_Delete,        ShiftMask,      "\033[2K",      -1,    0,    0},
 	{ XK_Delete,        ShiftMask,      "\033[3;2~",    +1,    0,    0},
-	{ XK_Delete,        XK_ANY_MOD,     "\033[3~",      +1,    0,    0},
+	{ XK_Delete,        XK_ANY_MOD,     "\033[P",       -1,    0,    0},
+	{ XK_Delete,        XK_ANY_MOD,     "\177",         +1,    0,    0},
 	{ XK_Home,          ShiftMask,      "\033[2J",       0,   -1,    0},
 	{ XK_Home,          ShiftMask,      "\033[1;2H",     0,   +1,    0},
 	{ XK_Home,          XK_ANY_MOD,     "\033[H",        0,   -1,    0},

st.info

@@ -73,7 +73,7 @@ st| simpleterm,
 	kri=\E[1;2A,
 	kclr=\E[3;5~,
 	kdl1=\E[3;2~,
-	kdch1=\E[3~,
+	kdch1=\0177,
 	kich1=\E[2~,
 	kend=\E[4~,
 	kf1=\EOP,