Add syntactic sugar for "__newindex"

[codyduong]

This is an extension of this discussion, which was resolved to support __index

Why support this syntax at all? No need to store r#type as a struct member.

This is for greater discussion on supporting syntactic sugar such as type, format

I have am having trouble with using methods.add_meta_method("__newindex", ... which is holding back most of the work on syntactic sugar. Either convert this to get_type or a method rather than a "field"

If we remove it be sure to remove r#type declarations here

hitokage/hitokage-lua/src/widgets/mod.rs

Lines 18 to 42 in 0679370

	impl<'lua> IntoLua<'lua> for WidgetUserData {
	fn into_lua(self, lua: &'lua Lua) -> mlua::Result<mlua::Value<'lua>> {
	match self {
	WidgetUserData::Clock(sender) => {
	let clock_userdata = ClockUserData {
	r#type: "Clock".to_string(),
	sender: sender,
	};
	lua.pack(clock_userdata)
	}
	WidgetUserData::Workspace(_) => {
	let workspace_userdata = WorkspaceUserData {
	r#type: "Workspace".to_string(),
	};
	lua.pack(workspace_userdata)
	}
	WidgetUserData::Box(_) => {
	let box_userdata = BoxUserData {
	r#type: "Box".to_string(),
	};
	lua.pack(box_userdata)
	}
	}
	}
	}

Originally posted by @codyduong in #9 (comment)

A consideration for adding support is that we must consider method accesses as well (they are themselves a user of "__newindex", which complicates this implementation