ncplayer: list octant blitter in help

src/player/play.cpp

@@ -30,7 +30,7 @@ void usage(std::ostream& o, const char* name, int exitcode){
   o << " -t seconds: delay t seconds after each file\n";
   o << " -l loglevel: integer between 0 and 7, goes to stderr\n";
   o << " -s scaling: one of 'none', 'hires', 'scale', 'scalehi', or 'stretch'\n";
-  o << " -b blitter: one of 'ascii', 'half', 'quad', 'sex', 'braille', or 'pixel'\n";
+  o << " -b blitter: one of 'ascii', 'half', 'quad', 'sex', 'oct', 'braille', or 'pixel'\n";
   o << " -m margins: margin, or 4 comma-separated margins\n";
   o << " -a color: replace color with a transparent channel\n";
   o << " -n: force non-interpolative scaling\n";