Add st-mono terminfo entry

This entry is intended for monocolor display and it is very
helpful for color haters.

st.info

@@ -1,4 +1,4 @@
-st| simpleterm,
+st-mono| simpleterm monocolor,
 	acsc=+C\,D-A.B0E``aaffgghFiGjjkkllmmnnooppqqrrssttuuvvwwxxyyzz{{||}}~~,
 	am,
 	bce,
@@ -10,7 +10,7 @@ st| simpleterm,
 	civis=\E[?25l,
 	clear=\E[H\E[2J,
 	cnorm=\E[?12l\E[?25h,
-	colors#8,
+	colors#2,
 	cols#80,
 	cr=^M,
 	csr=\E[%i%p1%d;%p2%dr,
@@ -168,13 +168,8 @@ st| simpleterm,
 	rs1=\Ec,
 	rs2=\E[4l\E>\E[?1034l,
 	sc=\E7,
-	setab=\E[4%p1%dm,
-	setaf=\E[3%p1%dm,
-	setb=\E[4%?%p1%{1}%=%t4%e%p1%{3}%=%t6%e%p1%{4}%=%t1%e%p1%{6}%=%t3%e%p1%d%;m,
-	setf=\E[3%?%p1%{1}%=%t4%e%p1%{3}%=%t6%e%p1%{4}%=%t1%e%p1%{6}%=%t3%e%p1%d%;m,
-	sgr0=\E[0m,
-	sgr=%?%p9%t\E(0%e\E(B%;\E[0%?%p6%t;1%;%?%p2%t;4%;%?%p1%p3%|%t;7%;%?%p4%t;5%;%?%p7%t;8%;m,
 	sitm=\E[3m,
+	sgr0=\E[0m,
 	smacs=\E(0,
 	smcup=\E[?1049h,
 	smir=\E[4h,
@@ -194,6 +189,15 @@ st| simpleterm,
 	Se=\E[2 q,
 	Ss=\E[%p1%d q,
 
+st| simpleterm,
+	use=st-mono,
+	colors#8,
+	setab=\E[4%p1%dm,
+	setaf=\E[3%p1%dm,
+	setb=\E[4%?%p1%{1}%=%t4%e%p1%{3}%=%t6%e%p1%{4}%=%t1%e%p1%{6}%=%t3%e%p1%d%;m,
+	setf=\E[3%?%p1%{1}%=%t4%e%p1%{3}%=%t6%e%p1%{4}%=%t1%e%p1%{6}%=%t3%e%p1%d%;m,
+	sgr=%?%p9%t\E(0%e\E(B%;\E[0%?%p6%t;1%;%?%p2%t;4%;%?%p1%p3%|%t;7%;%?%p4%t;5%;%?%p7%t;8%;m,
+
 st-256color| simpleterm with 256 colors,
 	use=st,
 	ccc,