gh-149720: Fix docs for `mimetypes.MimeType.add_type` method`
When *strict* is ``True`` (the default), the mapping will be added to the
official MIME types, otherwise to the non-standard ones.
- .. deprecated-removed:: 3.14 3.16
- Invalid, undotted extensions will raise a
- :exc:`ValueError` in Python 3.16.
+ .. deprecated:: 3.14
+ *ext* values that do not start with ``'.'`` are deprecated.
+
+ .. versionchanged:: next
+ *ext* now must start with ``'.'``. Otherwise :exc:`ValueError` is raised.
.. _mimetypes-cli: