chabrier1998 screening with quantum corrections can give enhancement factors < 1

[yut23]

I'm getting screening factors of 0 in test_screening when using chabrier1998 with quantum corrections enabled. At low temperature and high density, we're way outside the bounds of the fit from Alastuey & Jancovici 1978, 0 ≤ b ≤ 1.6. b is ~30 in the lower right corner of this plot of h12 (log of the screening factor) from test_screening. I had to set the range manually, the values actually go down to -1e10: