Handle properly stringifying multiline calls

[Blacksmoke16]

Previously code like:

{%
  vals = [4, 1, 12]
    .sort_by do |v| v end
    .map do |v| v end
%}

{%
  vals = "foo"
    .strip
    .strip.strip
%}

Would always be stringified as:

{%
  vals = [4, 1, 12].sort_by do |v| v end.map do |v| v end
%}

{%
  vals = "foo".strip.strip.strip
%}

With this PR it now remains unchanged.