A builder is uniquely identified by its name, which can be used as an
entry point in the 'sphinx.builders' entry point group. This obviates
the need to register the builder as an extension.
The built-in builders are still loaded as before. New third-party builders
should provide an entry point in their setup.py:
entry_points={
'sphinx.builders': [
'mybuilder = mypackage.mymodule:MyBuilder',
],
}
Like before, builders should define a setup(app) function in the
'mypackage.module' module to define configuration variables etc. It is
no longer necessary to register the builder using Sphinx.add_builder().
Existing builders can still be loaded the traditional way, by including
their module name in the extensions list in conf.py.
