* update article content to markdown ui component
* decouple lunr indexing from class name
* remove summary outline none rule, apply utility class instead
* improve typing
* scope more styles down to markdown-body/extended-markdown
* move all markdown-body style overrides to MarkdownContent component
* fix class targeting within css module
* clean up MarkdownContent header style
* rename data-lunr to data-search
* fix: inline code color issue
* fix: update article markdown to work with MarkdownContent
* pull changes from docs-playground
* cleanup, add callout banner
* cleanup linting and test fixes
* add discussion link
Co-authored-by: James M. Greene <JamesMGreene@github.com>
