docs(expandable section): update icon name in docs

Author: andrew-ronaldson

packages/documentation-site/patternfly-docs/content/components/expandable-section/expandable-section.md

@@ -12,7 +12,7 @@ An expandable section has two main elements.
 ![Elements of an expandable section.](./img/exp-sect-elements.svg)
 </div>
 
-1. **Toggle (fa-angle-right):** Indicates whether the section is expanded or collapsed.
+1. **Toggle:** Indicates whether the section is collapsed (rh-micron-caret-down) or expanded (rh-micron-caret-up).
 2. **Toggle text:** Informs the user what will be shown when the component is expanded.
 
 ## Usage