[Masonry] Adding a description and removing compat features (#707)

* Adding a description for Masonry and removing compat features

* Update feature-group-definitions/masonry.yml

Co-authored-by: Daniel D. Beck <daniel@ddbeck.com>

---------

Co-authored-by: Daniel D. Beck <daniel@ddbeck.com>

feature-group-definitions/masonry.yml

@@ -1,11 +1,6 @@
 name: Masonry
+description: Masonry is a type of CSS grid layout where the items on one of the axes are tightly packed together, like brickwork, instead of leaving gaps to align across the other axis.
 spec: https://drafts.csswg.org/css-grid-3/
 status:
   baseline: false
   support: {}
-compat_features:
-  - css.properties.align-tracks
-  - css.properties.grid-template-columns.masonry
-  - css.properties.grid-template-rows.masonry
-  - css.properties.justify-tracks
-  - css.properties.masonry-auto-flow