[BUGFIX] Update misleading Changelog documentation

This patch updates the Changelog documentation and suggests to use one
of the keywords "small", "medium", or "large" (instead of numeric
values) when registering dashboard widgets.

Resolves: #91041
Releases: master
Change-Id: I9b1ac49d8586ab058cd7278eadaba42df4fc05fe
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/64179


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Josef Glatz <josefglatz@gmail.com>
Tested-by: Richard Haeser <richard@maxserv.com>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Josef Glatz <josefglatz@gmail.com>
Reviewed-by: Richard Haeser <richard@maxserv.com>

typo3/sysext/core/Documentation/Changelog/master/Breaking-90660-RegistrationOfWidgetsChanged.rst

@@ -84,8 +84,8 @@ a little bit.
          title: 'LLL:EXT:extension/Resources/Private/Language/locallang.xlf:widgets.myOwnRSSWidget.title'
          description: 'LLL:EXT:extension/Resources/Private/Language/locallang.xlf:widgets.myOwnRSSWidget.description'
          iconIdentifier: 'content-widget-rss'
-         height: 4
-         width: 4
+         height: 'medium'
+         width: 'medium'
 
 It starts with the name of the service. Best practise is to use a dot-styled
 name as there will be now class with that name. On the second line, we define
@@ -103,6 +103,9 @@ You can still use translatable strings like
 Important to remember is that the :yaml:`widgetGroups`` property changed to :yaml:`groupNames`
 to stay consistent with other service registrations.
 
+Please note that valid values for height and width are now: `small`, `medium`,
+and `large`.
+
 In the following table you can see which WidgetType to use now based on the
 abstract you used previously.