feat(markdown): Support for custom components (#17)
* feat(markdown): Support for custom components
* fix: remove example
* remove handles
* fix: use different structs
* fix: don't run components if there's none
* feat: options
* fix: no idea what I'm doing
* fix: import
* fix: refactor
* fix: move tests
* fix: move tests
* fix: enum for blockquotes
* fix: link types
* feat: add everything else
* feat: example
* fix: some cleanup
* fix: simplify heading example
* fix: comments