Eric Huss d7892f5601 Add optional field for preprocessors ... This adds the `optional` field to the preprocessor configuration to mirror the same option for the `output` table. Missing preprocessors are now an error unless the `optional` field is set. This should help with inadvertently building a book when a missing preprocessor that you expect to be installed.		2025-08-16 13:39:54 -07:00
..
failing_preprocessor	Migrate ask_the_preprocessor_to_blow_up to BookTest	2025-04-22 20:50:20 -07:00
missing_optional_not_fatal	Add optional field for preprocessors	2025-08-16 13:39:54 -07:00
missing_preprocessor	Add a test for a missing preprocessor	2025-08-16 13:33:38 -07:00
nop_preprocessor	Migrate process_the_dummy_book to BookTest	2025-04-22 20:50:20 -07:00