Petri net docs

[jcrozum]

Added parameter and return values to Petri net docs, and renamed the ctx context variable to something more clear. Should be no meaningful changes to the code itself, so I will merge as soon as all tests pass.

[github-actions]

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	149	11	93%	22–26, 79, 136, 305–306, 330–331, 340, 449
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	1468	103	93%

Tests	Skipped	Failures	Errors	Time
361	0 💤	0 ❌	0 🔥	38.298s ⏱️