Infer line count from file instead of using parser newlines

librubyfmt/rubyfmt_lib.rb

@@ -66,16 +66,10 @@ def initialize(file_data)
     @rbracket_stack = []
     @lbrace_stack = []
     @comments = {}
-    @last_ln = 0
     # binary contents comming after a `__END__` node
     @data_contents_start_line = nil
   end
 
-  def on_nl(*args)
-    @last_ln = lineno+1
-    super(*args)
-  end
-
   # This method has incorrect behavior inside Ripper,
   # so we patch it for now
   # original: https://github.com/ruby/ruby/blob/118368c1dd9304c0c21a4437016af235bd9b8438/ext/ripper/lib/ripper/sexp.rb#L144-L155
@@ -113,7 +107,7 @@ def parse
         nil
       end
 
-      [res, @comments, @lines_with_any_ruby, @last_ln, data_contents]
+      [res, @comments, @lines_with_any_ruby, @file_lines.count, data_contents]
     end
   end