Fast forwarding as function arguments

- use `const &` for [big type] argument
- use `universal reference` to forward template argument
- use `std::forward` to forward template argument
```c++
auto function(std::vector& list, big_type case1, const big_type& case2, auto&& case3)
{
list.push_back(std::move(case1)) // one copy/only move, but call function(list, std::move(val), ..., ...)
list.push_back(case2) // always one copy
list.push_back(std::forward(case3)) // same case1 but have other features
}
```
```c++
auto function(big_type case1, const big_type& case2, auto&& case3)
{
case1.readonly_func() // (( always one copy
case2.readonly_func() // )) no copy
case3.readonly_func() // )) no copy
}
```

No files, tests, or entry points are identified. Use the C++ examples in the issue as the behavioral reference, first locating the transformer entry point that emits function arguments and any existing tests for generated signatures. Done means the intended forwarding behavior is specified and covered by tests.

Written by the indexing model from the issue text.