Unwanted new line characters within lists with paragraphs

[diogoosorio]

The library is adding what I believe to be unintended newline characters, when parsing a document with li > p structure with newlines in between the 2 nodes:

[6] pry(main)> ReverseMarkdown.convert("<ul> <li><p>a</p></li></ul>")
=> "- a\n\n"
[7] pry(main)> ReverseMarkdown.convert("<ul><li><p>a</p></li></ul>")
=> "- a\n\n"
[8] pry(main)> ReverseMarkdown.convert("<ul><li> <p>a</p></li></ul>")
=> "-  \n\na\n\n"
[9] pry(main)> ReverseMarkdown.convert("<ul><li>\n<p>a</p>\n</li></ul>")
=> "- \n\na\n\n"

The 2 first examples work as intended, but if you add a space or newline character between the <li> and the <p> the library changes its behaviour and introduces the problem.

Funnily enough this scenario was accounted for in the list specs here, but the corresponding assertion is being skipped here - and it has been this way since 2012 (cd24cc3).

Anyway I'll open a PR shortly with a fix proposal. 👍

[diogoosorio]

Oh and I forgot, this is where we "caught" the problem: forem/forem#10664