Frontmatter UI interaction improvements

[tlrand]

This specific request is not for frontmattter metadata support, but in terms of how FSNotes handles a documents that use the front matter conventions.

The request:

1. For the Notes List short-previews and automatic file naming disregard the frontmatter block
2. Do not do any markdown processing on the block. In other words, in other words pass it as if it was code fenced when previewed or rendered. Alternatively this block could be stripped from previews.
3. Syntax highlighting in the editor would be great for the key-value pairs.

Gitlabs markdown has a very nice solve for this.

This would improve interoperability with other tools (such as Obsidian and some CMS's, as well as giving a simple mechanism for text based metadata at the document level.

Edit to include Gitlabs link.