* AIR: add `mod` instruction for modulus division
   - Implement for LLVM backend
 * Sema: implement `@mod`, `@rem`, and `%`.
 * Sema: fix comptime switch evaluation
 * Sema: implement comptime shift left
 * Sema: fix the logic inside analyzeArithmetic to handle all the
   nuances between the different mathematical operations.
   - Implement comptime wrapping operations