fix: update mo2 'getprefix' arg to match help docs (#1099)

steamtinkerlaunch

@@ -22581,7 +22581,7 @@ function commandline {
 					writelog "INFO" "${FUNCNAME[0]} - URL passed is '$3'"
 					dlMod2nexurl "$3"
 				fi
-			elif [ "$2" == "getpfx" ] || [ "$2" == "gp" ]; then
+			elif [ "$2" == "getprefix" ] || [ "$2" == "gp" ]; then
 				echo "$MO2COMPDATA/pfx"
 			elif [ "$2" == "repairpfx" ]; then
 				setMO2Vars