Hashtag rendering in Table of Contents

[Maarrk]

Related to #759 and #867 (both fixed by #887)

Observed: Hashtag contents are missing from links in Table of Contents. Hashtag-only headers are rendered as links to the current page with @ position and empty | alias.

Expected: Hashtag contents are rendered in ToC, with or without the leading #, but without < > if used

Repro:

• Have the Core library installed
• Place a hashtag in a header
• Write enough headers to show Table of Contents, for example:

## Some header

## #only-hashtag

## #<also escaped>

## Header with #hashtag

## #hashtag and content

## Put #hashtag in the middle