Interpret newlines as line breaks when converting Markdown to HTML

[ulyssa]

When messages are typed in Element, it has a special case for interpreting newlines typed in the bar as <br/> tags instead of as a continuation of the current paragraph, which is the typical Markdown behaviour. This is more friendly towards the usual expectations in a chat client, where people usually type their paragraphs on one continuous line that wraps, instead of paragraphs that are split across multiple lines so that each one fits within a column limit.

iamb is currently using the markdown feature of the ruma crate to take care of converting Markdown to a formatted message, which uses the pulldown_cmark crate. The crate supports several parser options that can be used to change the default behaviour. None of them currently support this behaviour, but it might be possible to either add a new option to the crate, or to massage the input before it's handed over.

[ulyssa]

The comrak crate has a hardbreaks option that you can use when rendering HTML.