gh-34995: Support for tachyon >= 0.99.2
Taken from #23712.
This is necessary to support tachyon >= 0.99.2, without losing support
for older versions of tachyon.
In case #23712 gets delayed, it'd be nice to include this so nothing
breaks if system tachyon is updated. This is the first commit from the
branch there which already had positive review (the actual update of
tachyon has an issue mentioned in
https://github.com/sagemath/sage/issues/23712#issuecomment-1417941925.)
_From the commit log:_
In tachyon 0.99.2 the keyword `focallength` was changed to `focaldist`.
To support it, when running on version >= 0.99.2 we "patch" the model as
constructed by class `sage.plot.plot3d.tachyon.Tachyon`.
In the future (possibly when tachyon in sage gets upgraded), all the
focallength occurences in sage.plot.plot3d.tachyon can be replaced by
focaldist for consistency with new tachyon, and the logic here can be
reversed (i.e. patch the model when self.version() < '0.99.2') or just
drop support for old versions.
URL: https://github.com/sagemath/sage/pull/34995
Reported by: Gonzalo Tornaría
Reviewer(s): Matthias Köppe, Mauricio Collares
