`using for` with explicit function names does not support overloaded functions

## Description

When declaring functions to use with a user-defined type, overloaded functions trigger the error "Identifier not found or not unique".

## Environment

Solidity 0.8.13, 0.8.14

## Steps to Reproduce
```solidity
pragma solidity ^0.8.13;

type t is uint;

function f(t a) {}
function f(t a, bool b) {}

using {f} for t; // DeclarationError: Identifier not found or not unique.
```

## Suggestion

Allow specifying the overload to use ("`using {f(uint)} for t`") or always use all overloads with compatible signature.

Start with the Solidity reproduction using `type t is uint`, the overloaded `f` declarations, and `using {f} for t`. Compare the two proposed resolutions—explicit overload selection such as `using {f(uint)} for t` or allowing all compatible overloads—and define the intended behavior before locating the compiler entry point and adding coverage for the accepted syntax.

Written by the indexing model from the issue text.