Release 6.0.0-rc.1

This change also includes some minor packaging changes in order to make Cargo happy.

plugin/rbx_dom_lua/src/Error.lua

@@ -0,0 +1,28 @@
+local Error = {}
+Error.__index = Error
+
+Error.Kind = {
+	UnknownProperty = "UnknownProperty",
+	PropertyNotReadable = "PropertyNotReadable",
+	PropertyNotWritable = "PropertyNotWritable",
+	Roblox = "Roblox",
+}
+
+setmetatable(Error.Kind, {
+	__index = function(_, key)
+		error(("%q is not a valid member of Error.Kind"):format(tostring(key)), 2)
+	end,
+})
+
+function Error.new(kind, extra)
+	return setmetatable({
+		kind = kind,
+		extra = extra,
+	}, Error)
+end
+
+function Error:__tostring()
+	return ("Error(%s: %s)"):format(self.kind, tostring(self.extra))
+end
+
+return Error