Issue/830 Adds an escape for invisible paragraph separators

[frosty]

Fixes #830 – Adds another escape for invisible character separators.

See original issue for more info.

To test:

• Paste the following text into the editor, and toggle to the HTML view and back again:
  Paragraph
Paragraph
• Without this PR applied, you should see an error in the console similar to SyntaxError: Unexpected EOF
• With the PR applied, you should see no error.

Needs review: @diegoreymendez

[diegoreymendez]

Works perfectly to remove the issue.