rio(1) and rio(4) man page updates

sys/man/1/rio

@@ -13,6 +13,9 @@ rio, label, window, wloc \- window system
 .B -s
 ]
 [
+.B -b
+]
+[
 .B -f
 .I font
 ]
@@ -92,6 +95,10 @@ The
 option initializes windows so that text scrolls;
 the default is not to scroll.
 The
+.B -b
+option reverses the normal color sheme for windows, painting white
+text on a black background.
+The
 .I font
 argument names a font used to display text, both in
 .IR rio 's

sys/man/4/rio

@@ -8,9 +8,16 @@ rio \- window system files
 .BI ' cmd '
 ]
 [
+.B -k
+.BI ' kbdcmd '
+]
+[
 .B -s
 ]
 [
+.B -b
+]
+[
 .B -f
 .I font
 ]