Add annotation for documenting a module

[idanarye]

Lua modules can be created using:

---This is a module
local M = {}

---This is a function
function M.foo()
end

---This is another function
function M.bar()
end

return M

When I do it like this, foo and bar get their doc comment shown in the hover docs - but not in the generated JSON/Markdown documentation. The module itself does not even get its docstring to appear in the hover docs.

It'd be nice if we could somehow annotate that M is a module and have it appear as such in the hover docs and the generated JSON/Markdown documentation. It does when I make it a ---@class - but it's not a class and should not be treated as a class. ---@module is already taken for a different purpose, but maybe ---@mod (like in lemmy-help) or ---@library?