Document spotless formatting (including plugin and git hook setup)

[AdamZsofi]

No description provided.

[github-actions]

❗ Please modify build.gradle.kts to contain a later version than 6.7.2. Current version is 6.7.2.

[github-actions]

Benchexec test report for a selection of SV-Benchmarks (correct / incorrect / all):

Rundefinition	BOUNDED	CEGAR	HORN
SV-COMP25_no-data-race	❓ (0 / 0 / 31) HTML/CSV	❗ (6 / 1 / 10) HTML/CSV	❓ (0 / 0 / 31) HTML/CSV
SV-COMP25_no-overflow	❓ (0 / 0 / 4) HTML/CSV	❓ (0 / 0 / 4) HTML/CSV	❓ (0 / 0 / 4) HTML/CSV
SV-COMP25_termination	✅ (2 / 0 / 8) HTML/CSV	✅ (2 / 0 / 10) HTML/CSV	✅ (2 / 0 / 9) HTML/CSV
SV-COMP25_unreach-call	✅ (9 / 0 / 228) HTML/CSV	❗ (14 / 3 / 144) HTML/CSV	❗ (16 / 1 / 236) HTML/CSV
SV-COMP25_valid-memcleanup	❓ (0 / 0 / 32) HTML/CSV	❓ (0 / 0 / 33) HTML/CSV	❓ (0 / 0 / 33) HTML/CSV
SV-COMP25_valid-memsafety	❓ (0 / 0 / 173) HTML/CSV	✅ (20 / 0 / 132) HTML/CSV	❓ (0 / 0 / 161) HTML/CSV