Alias comments only show for strings and numbers

(Split from: https://github.com/LuaLS/lua-language-server/issues/2279)

Aliases have a feature where they can be multiline and you can write comments for different available values. However, this only works for string and numbers. For example in this code:

---@class TestClass

---@enum TestEnum
TestEnum = {
	TEST1 = 1,
	TEST2 = 2,
	TEST3 = 3,
}

---@alias TestAlias
---| 'TEST1' # TEST1 comment
---| 'TEST2' # TEST2 comment
---| 'TEST3' # TEST3 comment
---| TestClass # TestClass comment
---| TestEnum # TestEnum comment
---| TestEnum.TEST1 # TestEnum.TEST1 comment
---| 1 # TestNumber Comment

---@param test TestAlias
local function test(test)
end

test()

I get this

使用 issue 中的 alias 示例在 LuaLS 中复现该报告，然后追踪 string 值和数值的 alias 注释是如何被收集和显示的。对 TestClass、TestEnum 和 TestEnum.TEST1 检查相同的行为；当这些 alias 值的注释像 string 和数字的注释一样显示时，即表示完成。