Unclear that `config` named export is new in v3.0.0

[uncenter]

Support for a named config export from configuration files (11ty/eleventy#3246) was first released in v3.0.0, but the only note on https://www.11ty.dev/docs/config-shapes/ says that "Added in v3.0.0: Support for ESM and Asynchronous callbacks was added in Eleventy v3.0." As far as I can tell the config named export isn't ESM-specific or related to async, so maybe a new note should be added or the wording of this note could be changed to:

-Added in v3.0.0: Support for ESM and Asynchronous callbacks was added in Eleventy v3.0.
+Added in v3.0.0: Support for ESM, asynchronous callbacks, and the `config` named export were added in Eleventy v3.0.