* Add rule docs headings checker

* Fix typo in rule docs heading

* Standardize heading order in rule docs

* Add markdownlint

* Use `dash` style for all unordered lists

`ul-style` MarkdownLint rule

* Standardize unordered list indentation

`ul-indent` MarkdownLint rule

* Remove trailing spaces

`no-trailing-spaces` MarkdownLint rule

* Collapse consecutive empty lines

`no-multiple-blanks` MarkdownLint rule

* Add empty line after headings

`blanks-around-headings` MarkdownLint rule

* Add empty lines after code blocks

`blanks-around-fences` MarkdownLint rule

* Add empty lines before lists

`blanks-around-lists` MarkdownLint rule

* Add link title

`no-bare-urls` MarkdownLint rule

* Convert bold paragraph to heading

`no-emphasis-as-heading` MarkdownLint rule

* Fix trailing space in inline code

`no-space-in-code` MarkdownLint rule

* Add language to code blocks

`fenced-code-language` MarkdownLint rule

* Disable `no-inline-html` MarkdownLint rule in one place

* Fix wrong link syntax