Tiny change in keyboard shortcuts.

1. Add a keyboard shortcut 'h' as an alias for '?'. 'h' is quite common.
2. Advertise it in the banner, so people can discover all the other
shortcuts. Feel free to change the wording.

src/commands.c

@@ -216,14 +216,15 @@ void read_command(xmp_context handle, struct xmp_module_info *mi, struct control
 		}
 		break; }
 	case '?':
+	case 'c':
 	case 'i':
 	case 'I':
 	case 'S':
 	case 'm':
 		ctl->display = cmd;
 		break;
-	case 'c':
-		ctl->display = cmd;
+	case 'h':
+		ctl->display = '?';
 		break;
 	case '>':
 		change_sequence(handle, mi, ctl, 1);

src/main.c

@@ -278,6 +278,8 @@ int main(int argc, char **argv)
 		    opt.interp == XMP_INTERP_SPLINE ? "cubic spline interpolated " : "",
 		    opt.format & XMP_FORMAT_MONO ? "mono" : "stereo",
 		    opt.dsp & XMP_DSP_LOWPASS ? "" : " (no filter)");
+
+		report("Press h for help\n\n");
 	}
 
 	if (opt.probeonly) {