[new-feature] Exception re-raising

```ruby
rescue => error
  re_raise_as(SomeExceptionClass, error) # and custom message (may be)
end
```

```ruby
def re_raise_as(exception_klass, error) # and custom message (may be)
   exception = exception_klass.new(error.message)
   exception.set_backtrace(error.backtrace)
   raise(exception)
end
```