TrailingComma* styles don't correctly identify multiline literals

[fj]

# version
 ψ rubocop -V
0.36.0 (using Parser 2.3.0.2, running on ruby 2.3.0 x86_64-linux)

# .rubocop.yml
Style/TrailingCommaInArguments:
  EnforcedStyleForMultiline: no_comma

Style/TrailingCommaInLiteral:
  EnforcedStyleForMultiline: consistent_comma

# foo.rb
    let(:available_channels) { [{name: channel_name, api_identifier: channel_api_id}] }

Rubocop complains:

foo.rb:1:33: C: Style/TrailingCommaInLiteral: Put a comma after the last item of a multiline array.                                    
    let(:available_channels) { [{name: channel_name, api_identifier: channel_api_id}] }
                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

but this is not a multiline array; in fact, there's only one line in the whole file so it can't be a multiline array by definition!

[Annih]

Hello,

I think I found the root cause of this issue, and proposed a patch in #2757
After investigation it seems that the issue was only for single element array/hash, do you confirm @fj ?

Regards.