Improve binned_residuals()

[strengejacke]

Fixes #382

[codecov]

Codecov Report

Merging #641 (cfe551f) into main (3408a7c) will increase coverage by 0.15%.
The diff coverage is 91.48%.

❗ Current head cfe551f differs from pull request most recent head bf4b8ff. Consider uploading reports for the commit bf4b8ff to get more accurate results

@@            Coverage Diff             @@
##             main     #641      +/-   ##
==========================================
+ Coverage   54.98%   55.13%   +0.15%     
==========================================
  Files          84       84              
  Lines        5856     5878      +22     
==========================================
+ Hits         3220     3241      +21     
- Misses       2636     2637       +1     

Files	Coverage Δ
R/binned_residuals.R	74.11% <96.66%> (+7.45%)	⬆️
R/check_outliers.R	85.83% <98.11%> (ø)
R/check_model.R	31.29% <45.45%> (ø)