CVE-2026-16118: fix a heap out-of-bounds write in the little-endian byte-swap of
MIME magic values in _xdg_mime_magic_parse_magic_line()
(gio/xdgmime/xdgmimemagic.c) by parenthesizing (ptr + i) before the cast so the
write side uses byte offsets instead of scaling by the word size