fix: categories & tags tests.

[TooBug]

1. Fix categories and tags front matter .
2. Fix nested lists. (4 spaces or tab, not 2 spaces.)
3. Fix dl.(One dl tag with multi dt&dd tags are not rendered as intended.)

[SukkaW]

• Fix nested lists. (4 spaces or tab, not 2 spaces.)

Markdown supports 2 spaces indent. Just add extra 4 spaces and tab tests, leave 2 spaces ones as they are.

[TooBug]

@SukkaW Not really. Some packages allows 2 spaces, but not marked, which Hexo uses.

So the html is not correct if using 2 spaces, makes the tests no meaning, Because this beyond the responsibility of a theme, it's a renderer-issue.

[stevenjoezhang]

categories and tags front matter is working, even without indentation

https://hexo-optimize.pages.dev/all/2013/12/24/categories/ https://hexo-optimize.pages.dev/all/2013/12/24/tags/

[stevenjoezhang]

TOC in markdown.md is also broken, because of https://github.com/hexojs/hexo/issues/2137

Need to fix it somehow.