Allow OPT to modify -L

-L is a Boolean flag option, so you specify 'OPT L' or 'OPT !L'.

src/asm/rgbasm.5

@@ -1883,16 +1883,24 @@ can be used to change some of the options during assembling from within the sour
 takes a comma-separated list of options as its argument:
 .Bd -literal -offset indent
 PUSHO
-OPT   g.oOX ;Set the GB graphics constants to use these characters
-DW    `..ooOOXX
+    OPT g.oOX, !L  ; acts like command-line -g.oOX and omitting -L
+    DW `..ooOOXX   ; uses the graphics constant characters from OPT g
+    LD [$FF88], A  ; encoded as LD, not LDH
 POPO
-DW    `00112233
+    DW `00112233   ; uses the default graphics constant characters
+    LD [$FF88], A  ; optimized to use LDH if -L was passed
 .Ed
 .Pp
 The options that OPT can modify are currently:
-.Cm b , g
+.Cm b , g , p ,
 and
-.Cm p .
+.Cm L .
+The Boolean flag option
+.Cm L
+can be specified as
+.Ql OPT L
+or
+.Ql OPT !L .
 .Pp
 .Ic POPO
 and