Docs: Add eslint-config-mdcs to JSCS Migration Guide (#7737)

docs/user-guide/migrating-from-jscs.md

@@ -59,7 +59,7 @@ There are shareable configs available for most JSCS presets. The equivalent shar
 | `grunt`        | [`eslint-config-grunt`](https://github.com/markelog/eslint-config-grunt) |
 | `idiomatic`        | [`eslint-config-idiomatic`](https://github.com/jamespamplin/eslint-config-idiomatic) |
 | `jquery`        | [`eslint-config-jquery`](https://github.com/jquery/eslint-config-jquery) |
-| `mdcs`        | (not available) |
+| `mdcs`        | [`eslint-config-mdcs`](https://github.com/zz85/mrdoobapproves) |
 | `node-style-guide`        | [`eslint-config-node-style-guide`](https://github.com/pdehaan/eslint-config-node-style-guide) |
 | `wikimedia`        | [`eslint-config-wikimedia`](https://github.com/markelog/eslint-config-wikimedia) |
 | `wordpress`        | [`eslint-config-wordpress`](https://github.com/ntwb/eslint-config-wordpress) |