[FR] Show "LuaHelper" in the status bar _only_ when the file type is `.lua`

[wenfangdu]

Currently, after opening a .lua file, "LuaHelper" shows up in the status bar, even after swithing to another file type, e.g. .js, "LuaHelper" still persists. Please show "LuaHelper" in the status bar only when the file type is .lua.

Side note: clicking on "LuaHelper" does nothing is also kinda weird, for other extensions, clicking on the status bar icon usually opens a popup menu.