More robust trailing expressions newline implementation

[Blacksmoke16]

Follow up to #15305 to handle another edge case I noticed.

Before this PR if you had a macro expression whose body is an Expressions node, and the last node of those expressions was a Block or If statement, the end keyword would be on the wrong line. For example

{%
  to_process = [] of Nil

  to_process.each do
    b = 2
    a = 1
  end
%}

would be stringified as:

{%
  to_process = [] of Nil

  to_process.each do
    b = 2
    a = 1 end
%}

This PR resolves this and adds more test coverage on similar cases.

Supersedes #15613

[straight-shoota]

Why tag this as topic:lang:macros? This doesn't change macros on the language level. It's just a compiler change related to syntax representation, which is usually tagged as compiler:parser. So I think this was previously correct.

[Blacksmoke16]

My thinking was that stringification is related to macros so this might results in more accurate macro expansion errors. But not entirely sure that's accurate.

Yea, if you have:

macro finished
  {% verbatim do %}
    {%
      to_process = [] of Nil

      to_process.each do
        b = 2
        a = 1
      end

      raise "oh noes"
    %}
  {% end %}
end

Without this PR:

$ crystal run --error-trace test.cr
In test.cr:1:1

 1 | macro finished
     ^
Error: expanding macro

...

 >  1 |
 >  2 |     {%
 >  3 |   to_process = [] of Nil
 >  4 |
 >  5 |   to_process.each do
 >  6 |     b = 2
 >  7 |     a = 1  end
 >  8 |
 >  9 |   raise("oh noes")
 > 10 | %}
 > 11 |
Error: oh noes

With this PR:

$ ccrystal run --error-trace test.cr
Using compiled compiler at /home/george/dev/git/crystal/.build/crystal
In test.cr:1:1

 1 | macro finished
     ^
Error: expanding macro

...

 >  1 |
 >  2 |     {%
 >  3 |   to_process = [] of Nil
 >  4 |
 >  5 |   to_process.each do
 >  6 |     b = 2
 >  7 |     a = 1
 >  8 |   end
 >  9 |
 > 10 |   raise("oh noes")
 > 11 | %}
 > 12 |
Error: oh noes

[straight-shoota]

No, this is really just compiler behaviour. Not a language feature change.