Update building_documentation.md

[ljhwang]

Minor cosmetic changes.

[github-actions]

Benchmark	Main	Feature	Difference (99.9% CI)
Slab interpolation simple none	1.015 ± 0.005 (s=445)	1.021 ± 0.005 (s=441)	+0.6% .. +0.8%
Slab interpolation curved simple none	1.017 ± 0.004 (s=433)	1.022 ± 0.004 (s=452)	+0.5% .. +0.6%
Spherical slab interpolation simple none	1.186 ± 0.008 (s=376)	1.185 ± 0.006 (s=385)	-0.2% .. +0.1%
Slab interpolation simple curved CMS	1.069 ± 0.004 (s=431)	1.071 ± 0.005 (s=413)	+0.2% .. +0.4%
Spherical slab interpolation simple CMS	1.593 ± 0.011 (s=269)	1.595 ± 0.010 (s=298)	-0.1% .. +0.3%
Spherical fault interpolation simple none	1.191 ± 0.006 (s=392)	1.189 ± 0.006 (s=367)	-0.3% .. -0.0%
Cartesian min max surface	2.337 ± 0.018 (s=217)	2.337 ± 0.018 (s=171)	-0.3% .. +0.3%
Spherical min max surface	7.326 ± 0.030 (s=74)	7.326 ± 0.043 (s=51)	-0.3% .. +0.3%