Add linter, doctests

[ReubenJ]

All changes in src and test are a result of running the formatting script.

[codecov]

Codecov Report

Attention: Patch coverage is 72.41379% with 64 lines in your changes missing coverage. Please review.

Project coverage is 75.17%. Comparing base (9f199f4) to head (a9aa1a6).

Files with missing lines	Patch %	Lines
src/solver/uniform_solver/state_hole.jl	55.55%	12 Missing ⚠️
src/csg_annotated/csg_annotated.jl	0.00%	6 Missing ⚠️
src/solver/generic_solver/treemanipulations.jl	62.50%	6 Missing ⚠️
src/localconstraints/local_contains.jl	0.00%	5 Missing ⚠️
src/localconstraints/local_ordered.jl	0.00%	5 Missing ⚠️
src/grammarconstraints/forbidden.jl	55.55%	4 Missing ⚠️
src/grammarconstraints/ordered.jl	33.33%	4 Missing ⚠️
src/localconstraints/local_contains_subtree.jl	70.00%	3 Missing ⚠️
src/localconstraints/local_forbidden.jl	0.00%	3 Missing ⚠️
src/solver/uniform_solver/uniform_solver.jl	70.00%	3 Missing ⚠️
... and 10 more

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #63      +/-   ##
==========================================
- Coverage   75.47%   75.17%   -0.30%     
==========================================
  Files          31       31              
  Lines        1382     1402      +20     
==========================================
+ Hits         1043     1054      +11     
- Misses        339      348       +9     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.