Hello everyone,

I would like to propose the introduction of a new face:
org-agenda-calendar-timerange.
It is used to show entries with a timerange in the agenda, that is,
entries with a timestamp of the form:
<2022-12-22 Thu>--<2023-01-01 Sun>
At the moment, these entries with a timerange use the default face.
Please find attached a patch.

This is my first contribution (I just finished the copyright assignment
process with the FSF), so any feedback would be greatly appreciated.

In particular, could someone confirm that the function
org-agenda-get-blocks is the right place to apply the face? I place it
there mimicking how the faces org-agenda-calendar-event and
org-agenda-calendar-sexp are applied but I am not sure of this.

All the best,
Gautier.