lua: intf: luac: fix usage instructions

share/lua/intf/luac.lua

@@ -23,7 +23,7 @@
 usage = 
 [[
 To compile a lua script to bytecode (luac) run:
-  vlc -I luaintf --lua-intf --lua-config 'luac={input="file.lua",output="file.luac"}'
+  vlc -I luaintf --lua-intf luac --lua-config 'luac={input="file.lua",output="file.luac"}'
 Output will be similar to that of the luac command line tool provided with lua with the following arguments:
   luac -o file.luac file.lua
 ]]