Clarify bitmagic.
Clarify bitmagic.

[skip ci]

bertptrs/adventofcode,bertptrs/adventofcode,bertptrs/adventofcode,bertptrs/adventofcode,bertptrs/adventofcode,bertptrs/adventofcode,bertptrs/adventofcode,bertptrs/adventofcode,bertptrs/adventofcode,bertptrs/adventofcode,bertptrs/adventofcode,bertptrs/adventofcode,bertptrs/adventofcode,bertptrs/adventofcode,bertptrs/adventofcode,bertptrs/adventofcode