Outdated doc on first page code snippet

The code snippet on the page What is PESummary?

from pesummary.core.plots.main import _CorePlotGeneration
from pesummary.core.webpage.main import _CoreWebpageGeneration
plotting_object = _CorePlotGeneration(
   webdir="/home/albert.einstein/example", labels=["example"],
   samples=json_object.samples_dict
)
webpage_object = _CoreWebpageGeneration(
   webdir="/home/albert.einstein/example", labels=["example"],
   samples=json_object.samples_dict, user="albert.einstein",
   colors=["b"]
)

corresponding to this file references the classes _CorePlotGeneration and _CoreWebpageGeneration which do not exist anymore, replaced by _PlotGeneration and _WebpageGeneration.

My MR is ready to be pushed if that's okay !