Single Placeholder escaping is removed during formatting

[AngusMorton]

Single escaping of placeholders is lost during formatting. This seems like a bug because it changes the meaning of the output (AFAIK), but the tests indicate it's expected.

From the tests (placeholders-body-escaped.marko):

<div>
    Hello \${data.name}!
    Messages: \$!{data.messagesHtml}
</div>

Is formatted into (placeholders-body-escaped.expected/html.marko):

<div>Hello ${data.name}! Messages: $!{data.messagesHtml}</div>

I would have expected the escaping of the placeholder to be preserved in the formatted code:

<div>Hello \${data.name}! Messages: \$!{data.messagesHtml}</div>

I'm happy to work on a fix if this is indeed a bug.

[DylanPiercey]

That looks like a bug! If you're wanting to take a stab at fixing it that'd be much appreciated 🙏