Message parser doesn't handle CRLF linebreaks

[rafalp]

Markup:

Lorem ipsum

Dolor met

HTML result:

<p>Lorem Ipsum<br /><br />Dolor met</p>

Expected result:

<p>Lorem Ipsum</p>
<p>Dolor met</p>

This happens because parser expects LF (\n) input and browsers send CRLF (\r\n)

We can fix this in two steps:

• Run .replace("\r\n", "\n").replace("\r", "\n") to normalize newlines before we send the string deeper into parser.
• Do the .replace("\n", "\r\n") in reverse when rendering AST back to HTML/plaintext/etc.
• Replace \n with \r\n on formatting help page.

[rafalp]

We should also check all .join(”\n”) in codebase and change them to CRLF as part of this fix.

[raydeal]

Hi, I can work on this ticket.