Update 04_adding_first_tectonic_feature.md

[ljhwang]

Edits for clarity.

Please feel free to edit.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (5a44151) 92.80% compared to head (7ecfeac) 92.78%.
Report is 13 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #644      +/-   ##
==========================================
- Coverage   92.80%   92.78%   -0.02%     
==========================================
  Files          92       92              
  Lines        6474     6474              
==========================================
- Hits         6008     6007       -1     
- Misses        466      467       +1     

see 1 file with indirect coverage changes

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[github-actions]

Benchmark	Main	Feature	Difference (99.9% CI)
Slab interpolation simple none	1.017 ± 0.003 (s=457)	1.010 ± 0.003 (s=433)	-0.8% .. -0.7%
Slab interpolation curved simple none	1.015 ± 0.004 (s=440)	1.011 ± 0.003 (s=451)	-0.4% .. -0.3%
Spherical slab interpolation simple none	1.163 ± 0.006 (s=401)	1.164 ± 0.006 (s=375)	-0.0% .. +0.2%
Slab interpolation simple curved CMS	1.059 ± 0.004 (s=450)	1.057 ± 0.006 (s=403)	-0.3% .. -0.1%
Spherical slab interpolation simple CMS	1.546 ± 0.011 (s=288)	1.548 ± 0.013 (s=296)	-0.0% .. +0.4%
Spherical fault interpolation simple none	1.167 ± 0.006 (s=371)	1.171 ± 0.013 (s=401)	+0.2% .. +0.6%
Cartesian min max surface	2.300 ± 0.018 (s=211)	2.304 ± 0.041 (s=182)	-0.3% .. +0.6%
Spherical min max surface	7.221 ± 0.026 (s=65)	7.213 ± 0.026 (s=62)	-0.3% .. +0.1%