Format Markdown files with Markdownlint

[nschonni]

Took a quick pass over the files with Markdownlint-CLI2. Still 2 left over in docs/index.md for HTML elements.

Basic config of

{
    "config": {
        "default": true,
        "MD013": false
    }
}

Leaves the last 2 messages:

$ markdownlint-cli2-fix "**/*.md"
markdownlint-cli2-fix v0.6.0 (markdownlint v0.27.0)
Finding: **/*.md
Linting: 22 file(s)
Summary: 2 error(s)
docs/index.md:3:1 MD033/no-inline-html Inline HTML [Element: a]
docs/index.md:3:41 MD033/no-inline-html Inline HTML [Element: img]

[ohler55]

The docs directory looks like an experiment that didn't pan out so it can be removed.

[nschonni]

I think those files are for the GitHub pages https://ohler55.github.io/oj/
Do you want me to remove the files and the _config.yml in the root? You'd probably need to turn off the Pages in the repo settings too

[ohler55]

I see, should probably leave them in place until I have a changes to see if GitHub Pages is being used or not.