Added

• New exercise: if3, teaching the user about if let statements.
• hashmaps2: Added an extra test function to check if the amount of fruits is higher than zero.
• enums3: Added a test for Message.
• if1: Added a test case to check equal values.
• if3: Added a note specifying that there are no test changes needed.

Changed

• Swapped the order of threads and smart pointer exercises.
• Rewrote the CLI to use clap - it's matured much since we switched to argh :)
• structs3: Switched from i32 to u32.
• move_semantics: Switched 1-4 to tests, and rewrote them to be way simpler, while still teaching about the same concepts.

Fixed

• iterators5:
  • Removed an outdated part of the hint.
  • Renamed variables to use snake_case.
• vecs2: Updated the hint to reference the renamed loop variable.
• enums3: Changed message string in test so that it gets properly tested.
• strings2: Corrected line number in hint, then removed it (this both happened as part of this release cycle).
• primitive_types4: Updated hint to the correct ending index.
• quiz1: Removed duplicated sentence from exercise comments.
• errors4: Improved comment.
• from_into: Fixed test values.
• cow1: Added .to_mut() to distinguish from the previous test case.
• threads2: Updated hint text to reference the correct book heading.

Housekeeping

• Cleaned up the explanation paragraphs at the start of each exercise.
• Lots of Nix housekeeping that I don't feel qualified to write about!
• Improved CI workflows, we're now testing on multiple platforms at once.