Added some redirects for versions 13 and 14

Author: sofietoft

13/umbraco-cms/.gitbook.yaml

@@ -12,3 +12,4 @@ redirects:
     extending/property-editors/build-a-block-editor: fundamentals/backoffice/property-editors/built-in-umbraco-property-editors/block-editor/README.md
     tutorials/creating-and-distributing-a-package: extending/packages/creating-a-package.md
     fundamentals/design/templates/razor-cheatsheet: fundamentals/design/templates/README.md
+    reference/management-api: reference/dive-into-the-code.md

14/umbraco-cms/.gitbook.yaml

@@ -131,4 +131,4 @@ redirects:
     customizing/property-editors/build-a-block-editor: fundamentals/backoffice/property-editors/built-in-umbraco-property-editors/block-editor/README.md
     tutorials/creating-and-distributing-a-package: extending/packages/creating-a-package.md
     fundamentals/design/templates/named-sections: fundamentals/design/templates/README.md
-    
+    extending-backoffice/customize-backoffice: customizing/README.md