Intersect. Theory: Code cleanup, correction, new example

[wdecker]

No description provided.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.60%. Comparing base (1217ab3) to head (801aca3).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4180      +/-   ##
==========================================
- Coverage   84.60%   84.60%   -0.01%     
==========================================
  Files         631      631              
  Lines       84811    84810       -1     
==========================================
- Hits        71751    71750       -1     
  Misses      13060    13060              

Files with missing lines	Coverage Δ
...ental/IntersectionTheory/src/IntersectionTheory.jl	100.00% <ø> (ø)
experimental/IntersectionTheory/src/Main.jl	92.90% <100.00%> (ø)
experimental/IntersectionTheory/src/blowup.jl	98.47% <100.00%> (-0.02%)	⬇️

[lgoettgens]

some misc comments, mostly whitespace