)

Co-authored-by: Chris Bottin <[email protected]>

Call require('ts-node').register() after checking configFilePath has `.ts` extension

Fixes #3329

Changes:

- Promote `require('karma-plugin')` form over `'karma-plugin'` form. Former makes it more clear that plugin is imported from an NPM package and it is a regular JS object, there is no magic behind it. This is inspired by #3498 where user is not aware that it is even possible. This also should make it easier with plug'n'play package managers (like Yarn 2).
- Explain that `plugins` array does not activate plugins, but only registers them to clarify #1247 (comment).
- Explain the plugin structure, DI and how to build a new plugin.
- Re-arrange "Developing plugins" page to make it easier to add more information about every plugin type. Adding actual information should be done in the separate PRs though.

Fixes #1247

## [6.1.1](v6.1.0...v6.1.1) (2021-02-12)

### Bug Fixes

* **config:** check extension before ts-node register ([#3651](#3651)) ([474f4e1](474f4e1)), closes [#3329](#3329)
* report launcher process error when exit event is not emitted ([#3647](#3647)) ([7ab86be](7ab86be))