Update powi.zig to fix docstring formatting

Without this change, the docs are formatted s.t. the text "Edge case rules ordered by precedence:" is appended onto the prior line of text "Underflow: Absolute value of result smaller than 1", instead of getting its own line.
718ee31e21Becker A. committed on 8/24/2025, 8:59:08 PM· committed by Alex Rønne Petersenparent83f773f
1 file changedLine totals unavailable