Operator overloading is not detected properly

[kenzocarneiro]

Describe the bug
When creating a class and overloading its operators, the extension doesn't seem to detect the new return value of the operation. The result is detected as a "number":

--- Class representing Vectors.
--- @class Vector
--- @field x number
--- @field y number
Vector = {}

--- Constructor of Vector.
--- @param x number
--- @param y number
--- @return Vector
function Vector:new(x, y)
    local e = {}
    setmetatable(e, self)
    self.__index = self
    e.x = x or 0
    e.y = y or 0
    return e
end

--- Add to another Vector.
--- @param v Vector
--- @return Vector
function Vector:__add(v)
    return Vector:new(self.x + v.x, self.y + v.y)
end

local v = Vector:new(3, 4)
v = v + Vector:new(1, 2) --- Warning here
print(v)

The __add function is detected:

But there is still a warning:

This may be related to #599, but I'm not sure.

To Reproduce
Create a class and overload the operators. (See the code above).

Expected behavior
This shouldn't trigger a warning: since __add is documented, the result of the operation should be detected as a Vector (or at least an "any" for a sum/div/... with tables).

Environment:

• OS: Windows 10 x64
• Is WSL remote? No
• Client: VSCode

[sumneko]

Same as #599