[TASK] Add stub for new TCA type "json"

Related: TYPO3-Documentation/Changelog-To-Doc#381
Releases: main, 12.4

Documentation/ColumnsConfig/Type/Json/Index.rst

@@ -0,0 +1,23 @@
+.. include:: /Includes.rst.txt
+
+.. _columns-json:
+
+====
+Json
+====
+
+..  versionadded:: 12.3
+    The TCA field type `json` has been added to TYPO3 Core.
+
+    When using the `json` type, TYPO3 takes care of
+    :ref:`generating the according database field <t3coreapi:auto-generated-db-structure>`.
+    A developer does not need to define this field in an extension's
+    :file:`ext_tables.sql` file.
+
+
+..  note::
+    Currently, we have not documented this TCA type in detail. In the meantime,
+    you can find more information in the according
+    :ref:`changelog <ext_core:feature-100088-1677965005>`. If you can
+    help us with setting up the documentation for this type, please provide
+    :ref:`a pull request <h2document:docs-contribute-git-docker>`.