Bangs with a `*` suffix (e.g. `!!d*`) overwrite Bangs with the same
prefix (e.g. `!!d`) [1]. This can be avoid when a non printable character is
used to tag a LEAF_KEY.
[1] https://github.com/searxng/searxng/pull/740#issuecomment-1010411888
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>