Idempotency Failure: UTF-8 BOM Causes Leading Blank Line

[nicholasdower]

Originally reported in #915

Commit: 95210d7

Input

The file begins with a UTF-8 BOM (EF BB BF):

printf '\xef\xbb\xbf# encoding: utf-8\n\nclass Foo\nend\n'

# encoding: utf-8

class Foo
end

Output

 
# encoding: utf-8
class Foo
end

Second Output

# encoding: utf-8
class Foo
end

Expected behavior

The output should be stable.

Found in: powerpack 0.1.3 (lib/powerpack/string/ascii_only.rb, spec/powerpack/string/ascii_only_spec.rb)