optimize TinyMCE upgrade notes.

Author: MrTango

docs/backend/upgrading/version-specific-migration/upgrade-to-60.md

@@ -553,7 +553,7 @@ In that case, you are advised to add the `image_scales` column manually to the c
 ## New version of TinyMCE
 
 Plone 6 ships with a new version of TinyMCE.
-While Mockup for Plone 5.2 ships with TinyMCE 4.7 Plone 6.0 ships with TinyMCE 5.10.
+While Plone 5.2 ships with TinyMCE 4.7, Plone 6.0 ships with TinyMCE 5.10.
 The TinyMCE integration, pat-tinymce has also changed, but the configuration options have been almost kept the same and are likely to be compatible with your existing installation.
 The configuration changes are:
 
@@ -566,8 +566,9 @@ But there is more.
 
 ### TinyMCE templates
 
-While in Plone 5 you had to enable the template plugin (which was already shipped but not exposed to the UI) via the `custom_plugins` configuration option, Plone 6 has this option built-in.
-But in Plone 6 your templates need to have a `description`, otherwise TinyMCE will throw an JavaScript error and the templates won't be usable at all.
+In Plone 6 the TinyMCE template plugin is build-in and can be enabled via checkbox.
+While in Plone 5 you had to enable the template plugin, as an external plugin via the `custom_plugins` configuration option.
+The template registration is the same as before, but in Plone 6 your templates need to have a `description`, otherwise TinyMCE will throw an JavaScript error and the templates won't be usable at all.
 
 This is an example `registry.xml` snippet for configuring TinyMCE with some templates:
 
@@ -600,11 +601,6 @@ This is an example `registry.xml` snippet for configuring TinyMCE with some temp
 Please make sure you write valid JSON for the `template` option.
 
 
-### Custom Plugins
-
-TODO
-
-
 ### More information on TinyMCE 4 to 5 migration
 
 For more information on the TinyMCE 4 to 5 upgrade consult the TinyMCE upgrade guide: https://www.tiny.cloud/docs/migration-from-4x/