list of component is out of date

[12rambau]

In our documentation in https://pydata-sphinx-theme--1409.org.readthedocs.build/en/1409/user_guide/layout.html#built-in-components-to-insert-into-sections, the build-in component list is out of date.

Maybe we could create a custom directive that read the content of src/theme/pydata-sphinx-theme/component so that we don't forget to update it again if/when we add one.