Improve Method Override support for tables with known types

[pouwelsjochem]

Environment（环境）

name	version
IDEA version	2020.2.4
EmmyLua version	1.3.4
OS	MacOS 10.15.7

What are the steps to reproduce this issue?（重现步骤？）

The following code can be used:

local t = {}

function t:new()
    local class = {} ---@class myClass

    ---@param _numberParam number
    function class:method(_numberParam)
        -- EmmyLua does know _numberParam is a number
    end

    return class
end

local classInstance1 = t:new() ---@type myClass
function classInstance1:method(_numberParam)
    -- EmmyLua does NOT know _numberParam is a number
end

local classInstance2 = t:new() ---@class myClassInstance : myClass
function classInstance2:method(_numberParam)
    -- EmmyLua does know _numberParam is a number
end

What happens?（出现什么问题？）

After overriding an instance method, EmmyLua only keeps parameter information when the instance is defined as a new class.

What were you expecting to happen?（期望？）

EmmaLua to understand parameter information after overriding a instance method with known type information. So referring to the code example, it would be great if it would work on classInstance1

[pouwelsjochem]

It does seem to work when myClass has another parent where the method is initially defined. I guess EmmyLua only defines it as an override when it's a named subclass, which makes sense. Although I would love to be able to create anonymous subclasses as well, perhaps with a new annotation? @subclassOf myClass / @extends myClass ?

local t = {}

function t:newParent()
    local class = {} ---@class myClassParent

    ---@param _numberParam number
    function class:method(_numberParam)
        -- EmmyLua does know _numberParam is a number
    end

    return class
end

function t:new()
    local class = {} ---@class myClass : myClassParent

    return class
end

local classInstance1 = t:new() ---@type myClass
function classInstance1:method(_numberParam)
    -- EmmyLua does know _numberParam is a number
end

local classInstance2 = t:new() ---@class myClassInstance : myClass
function classInstance2:method(_numberParam)
    -- EmmyLua does know _numberParam is a number
end