Clean replacement

[onespaceman]

Most of clean.ts can be replaced with good ol' css.

web/active_lines.ts applies a style to active and selected lines, replacing all the isCursorInRange checks, and iterating over the syntax tree and css does the rest. A change in behavior is that marks now are visible whenever its line is active, instead of within the element. I don't think I can easily change this behavior to the old way, so if it's unacceptable, feel free to reject the pr. I just need to know if it's worth continuing to work on this.

End goal:

• Command for toggling mark hiding on and off
• Marks can be set to turn translucent instead of hiding

Checklist

• [x] Text formatting marks
• [x] Links
• [x] Headings
• [x] Lists
• [x] Wikilinks
• [ ] Codeblocks
• [ ] Blockquotes
• [ ] Frontmatter
• [ ] Toggle command
• [ ] Figure out if configuring through styles is good enough or if it needs settings

[zefhemel]

This is very interesting. Let me play with this a little bit and see how it feels in practice.

[zefhemel]

Let's have a discussion here: https://community.silverbullet.md/t/request-for-feedback-testing/288

Honestly after playing with this a few minutes I'm not sure I like the expansion of the entire paragraph. Generally I don't like that text jumps when moving text around, although this is inherent in how live preview works. This jumping happens more often when all it requires is putting a cursor anywhere in the line, so... hmm.