Handle properly stringifying multiline named tuple literals

[Blacksmoke16]

Depends on, and is similar to, #15305 but for NamedTupleLiteral nodes.

Previously code like:

{%
  {
    id: 1, active: true,
    name: "foo".upcase,
    pie: 3.14,
  }
%}

Would always be stringified as:

{% {id: 1, active: true, name: "foo".upcase, pie: 3.14} %}

But now, in-conjunction with the other PR, results in:

{%
  {
    id: 1, active: true,
    name: "foo".upcase,
    pie: 3.14,
  }
%}

I threw a bunch of test cases at it with the assumption the code may not have had the formatter ran on it and all seems 👍.

Marking as draft and skipping CI. Will rebase/trigger CI once the other dependent PR is merged. But wanted to get this opened for feedback.

[Blacksmoke16]

There's at least one case somewhere where an empty named tuple literal is to be stringified. Having this early return prevents having to use .first? and .last? and dealing with nil.