markdownlint/doc-build/md022.md

This rule is triggered when headings (any style) are either not preceded or not followed by at least one blank line:

# Heading 1
Some text

Some more text
## Heading 2

To fix this, ensure that all headings have a blank line both before and after (except where the heading is at the beginning or end of the document):

# Heading 1

Some text

Some more text

## Heading 2

The lines_above and lines_below parameters can be used to specify a different number of blank lines (including 0) above or below each heading.

Note: If lines_above or lines_below are configured to require more than one blank line, MD012/no-multiple-blanks should also be customized.

Rationale: Aside from aesthetic reasons, some parsers, including kramdown, will not parse headings that don't have a blank line before, and will parse them as regular text.