update interpolation argument documentation

[tjhei]

also see #547

[MFraters]

one small comment, otherwise good to go.

[MFraters]

Could you add a note here that this parameter is deprecated?

[tjhei]

is this because the global one is also only "continuous monotone spline"?

[MFraters]

yes, and I probably want to get rid of this option before the 1.0 release.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (1ae31ff) 93.49% compared to head (9a62a04) 93.55%.
Report is 56 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #549      +/-   ##
==========================================
+ Coverage   93.49%   93.55%   +0.05%     
==========================================
  Files          92       92              
  Lines        6346     6343       -3     
==========================================
+ Hits         5933     5934       +1     
+ Misses        413      409       -4     

Files	Coverage Δ
source/world_builder/features/interface.cc	97.77% <ø> (ø)

... and 3 files with indirect coverage changes

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[github-actions]

Benchmark	Main	Feature	Difference (99.9% CI)
Slab interpolation simple none	1.023 ± 0.004 (s=413)	1.023 ± 0.004 (s=469)	-0.1% .. +0.1%
Slab interpolation curved simple none	1.026 ± 0.003 (s=454)	1.026 ± 0.002 (s=426)	-0.0% .. +0.1%
Spherical slab interpolation simple none	1.249 ± 0.012 (s=332)	1.243 ± 0.013 (s=393)	-0.7% .. -0.2%
Slab interpolation simple curved CMS	1.098 ± 0.008 (s=407)	1.100 ± 0.007 (s=414)	+0.0% .. +0.3%
Spherical slab interpolation simple CMS	1.864 ± 0.007 (s=236)	1.861 ± 0.005 (s=250)	-0.2% .. -0.1%
Spherical fault interpolation simple none	1.272 ± 0.005 (s=362)	1.269 ± 0.004 (s=349)	-0.4% .. -0.2%
Cartesian min max surface	2.415 ± 0.018 (s=205)	2.416 ± 0.018 (s=170)	-0.2% .. +0.3%
Spherical min max surface	7.359 ± 0.016 (s=61)	7.362 ± 0.023 (s=64)	-0.1% .. +0.2%

[tjhei]

updated.