* Use reference links in Markdown.
Fixes https://github.com/documentationjs/documentation/issues/948.
This approach might be problematic when inserting markdown under a readme heading if the readme already has link references with conflicting ID’s.
* Reference links edits:
- fix broken normalize() utility in test suite so that it produces
output that doesn't choke referenceLinks.
- add DocumentationConfig option `--noReferenceLinks` which will be
**internal only**, and turns off reference links for `readme` mode
- rebuilds test output with these changes
unrelated but minor
- includes .prettierrc and updates calls to prettier to use that instead
of CLI options
* chore: update test snapshots
* Update readme snap
* build: Use Flow syntax without comments.
We're switching to Flow annotations - not Flow comments. This
gives documentation.js the ability to self-document without
JSDoc types and improves our compatibility with tools like
prettier.
Fixes#729. Fixes#709
