Docs whatsnew add dropdowns to the template (#3969)

* add release highlights dropdown to latest and template

* add the patches dropdown to latest template

* make the patch release pulldown v3 generic

docs/iris/src/whatsnew/latest.rst

@@ -7,6 +7,21 @@ This document explains the changes made to Iris for this release
 (:doc:`View all changes <index>`.)
 
 
+.. dropdown:: :opticon:`report` Release Highlights
+   :container: + shadow
+   :title: text-primary text-center font-weight-bold
+   :body: bg-light
+   :animate: fade-in
+   :open:
+
+   The highlights for this major/minor release of Iris include:
+
+   * N/A
+
+   And finally, get in touch with us on `GitHub`_ if you have any issues or
+   feature requests for improving Iris. Enjoy!
+
+
 📢 Announcements
 ================
 
@@ -65,6 +80,8 @@ This document explains the changes made to Iris for this release
 #. `@rcomer`_ removed an old unused test file. (:pull:`3913`)
 
 
+
+.. _GitHub: https://github.com/SciTools/iris/issues/new/choose
 .. _@pelson: https://github.com/pelson
 .. _@trexfeathers: https://github.com/trexfeathers
 .. _@gcaria: https://github.com/gcaria

docs/iris/src/whatsnew/latest.rst.template

@@ -7,6 +7,33 @@ This document explains the changes made to Iris for this release
 (:doc:`View all changes <index>`.)
 
 
+.. dropdown:: :opticon:`alert` v3.X.X Patches
+   :container: + shadow
+   :title: text-primary text-center font-weight-bold
+   :body: bg-light
+   :animate: fade-in
+   :open:
+
+   The patches in this release of Iris include:
+
+   #. N/A
+
+
+.. dropdown:: :opticon:`report` Release Highlights
+   :container: + shadow
+   :title: text-primary text-center font-weight-bold
+   :body: bg-light
+   :animate: fade-in
+   :open:
+
+   The highlights for this major/minor release of Iris include:
+
+   * N/A
+
+   And finally, get in touch with us on `GitHub`_ if you have any issues or
+   feature requests for improving Iris. Enjoy!
+
+
 📢 Announcements
 ================
 
@@ -52,4 +79,9 @@ This document explains the changes made to Iris for this release
 💼 Internal
 ===========
 
-#. N/A
+* N/A
+
+
+
+
+.. _GitHub: https://github.com/SciTools/iris/issues/new/choose