Feature Request: Capture table keys similar to capturing generic types

I like TypeScript's keyof operator that basically suggests that the value of a given string must match one of the properties/keys of a specified object.

In Lua, a type declared as @type keyof queries would mean it is a string whose value is a key found in the queries table.

This is useful because I can change just the value types if the keys of a table parameter were to be captured and specified as the target for a returned table type.

Here's an example of what I currently have to show the problem:

---@param queries table<string, string>
---@return table<string, QueryResult?>
local function QueryMany(queries)
  local results = {}

  for key, query in pairs(queries) do
    results[key] = Query(query) -- this function returns `QueryResult?`
  end

  return results
end

So, you can see that the queries argument is a table, and the keys should be exactly the same in the returned table, but only the values change.

Therefore, when I hover over the returned table in VS Code it doesn't know the keys in the table and only shows the key as being a string.

In the example above, the new annotation would look like this:

---@param queries table<string, string>
---@return table<keyof queries, QueryResult?>

Currently, I need to create custom aliases or cast the returned tables manually when using the QueryMany example function to add the desired intelli-sense in VS Code. This is a problem because the function is designed to be dynamically reusable with arbitrary table arguments.

For context, this is how I would use the above function:

local results = QueryMany({
  xSpacing = "frame.dimensions.xSpacing",
  ySpacing = "frame.dimensions.ySpacing",
  vDirection = "frame.behavior.vDirection",
  hDirection = "frame.behavior.hDirection",
})

(in summary: the table is transformed from a key-value pair of string/string to string/QueryResult? and there is no way of telling LuaLS this without losing the field/key names)

You could also support keyof for standard aliases and types:

---@type keyof queries
local queryName = "" -- the value of queryName must match a field key found in the queries table

-- or as an alias:
---@alias QueryName keyof queries

Issue không nêu tên tệp repository, test hoặc entry point nào. Hãy bắt đầu bằng cách xác định phần xử lý hiện có đối với việc capture generic type và annotation, sau đó theo dõi cách các table key và alias được biểu diễn. Công việc được hoàn tất khi keyof queries giữ lại các key của bảng đầu vào cho các bảng được trả về và xác thực các giá trị độc lập hoặc alias dựa trên các key đó.