Prevent endless loop when setting deprecated jekyllDataString (renderer) prototype

[Witiko]

Since #451 from Markdown 3.7.0, the jekyllDataString (renderer) prototype has been deprecated in favor of the jekyllDataTypographicString alias. While the jekyllDataString (renderer) prototype is still produced by globbing, we no longer allow users to set it directly by an error in #451. Therefore, setting jekyllDataString (renderer) prototype or any glob that includes jekyllDataString will produce an endless loop, since any (renderer) prototype that cannot be set is considered a glob and will be expanded ad infinitum.

Tasks

• Allow renderer (prototype) jekyllDataString to be set.
• Do not provide default jekyllDataString renderer (prototype).
• Test that jekyllDataString renderer (prototype) can be set.
• Update CHANGES.md