Extending alias functionality [Suggestion]

Good day, my suggestion is quite unusual - I'm requesting an additional functionality for aliases, basically adding ability to define regexp for string-based aliases. For example I have something like this:

---@alias Identifier string

That makes type check that Identifier is a string, but don't check if identifier need a custom structure, for example if correct structure is something like namespace:path it can't be validated with LLS.

If on another hand I can able to add a regexp to it:

---@alias Identifier string("^[^:]*:[^:]*$")

Then it will automatically check if identifier is valid

Start by reviewing the existing alias type-checking behavior and how LuaLS represents string-based types. The requested syntax and regexp semantics need to be defined before implementation. Done should include regexp-constrained aliases such as Identifier being validated against the specified pattern.