Add short description for backwards incompatible changes

docs/CHANGELOG.md

@@ -5,8 +5,14 @@
 ### Backward incompatible changes
 
 - Change names of connector attributes ([#77](https://github.com/formatc1702/WireViz/issues/77), [#105](https://github.com/formatc1702/WireViz/pull/105))
+  - `pinnumbers` is now `pins`
+  - `pinout` is now `pinlabels`
 - Remove ferrules as a separate connector type ([#78](https://github.com/formatc1702/WireViz/issues/78), [#102](https://github.com/formatc1702/WireViz/pull/102))
+  - Simple connectors like ferrules are now defined using the `style: simple` attribute
 - Change the way loops are defined ([#79](https://github.com/formatc1702/WireViz/issues/79), [#75](https://github.com/formatc1702/WireViz/pull/75))
+  - Wires looping between two pins of the same connector are now handled via the connector's `loops` attribute.
+
+See the [syntax description](syntax.md) for details.
 
 
 ### New features