added docs for trappist_core module

[jcrozum]

Just modifying docstrings. Only change to the code is to the type annotations for the problem specification; they now enforce that we only handle "min", "max", or "fix" problem types (minimal/maximal trap spaces or fixed points).

[github-actions[bot]]

Coverage Report

File	Stmts	Miss	Cover	Missing
balm
control.py	114	14	88%	102, 114, 120, 124, 129, 138–154, 472, 475, 488
interaction_graph_utils.py	30	4	87%	6–8, 145–146
motif_avoidant.py	148	2	99%	25, 171
petri_net_translation.py	148	11	93%	18–22, 58, 94, 207–208, 232–233, 242, 346
space_utils.py	129	4	97%	25–27, 252, 278
succession_diagram.py	257	16	94%	6, 184–189, 197, 257–258, 268, 274, 390, 580, 772, 810, 847
symbolic_utils.py	26	3	88%	10–12, 44
trappist_core.py	183	30	84%	11–15, 52, 54, 89, 165, 212, 214, 216, 244–247, 251–253, 273–279, 337, 339, 369, 417, 419, 450, 502
balm/_sd_algorithms
compute_attractor_seeds.py	30	1	97%	8
expand_attractor_seeds.py	51	5	90%	6, 42, 97–102
expand_bfs.py	28	1	96%	6
expand_dfs.py	30	1	97%	6
expand_minimal_spaces.py	37	2	95%	6, 31
expand_source_SCCs.py	164	6	96%	19–21, 91, 101, 143, 287
expand_to_target.py	31	3	90%	6, 38, 43
TOTAL	1467	103	93%

Tests	Skipped	Failures	Errors	Time
361	0 :zzz:	0 :x:	0 :fire:	1m 7s :stopwatch:

[jcrozum]

I'm going to merge this without review because the changes are minor.