In Crystal, handling multi-byte sequences in UTF-8 requires understanding that
slicing by bytes can lead to invalid sequences if the slicing isn't aligned
with character boundaries. In this case, attempting to slice a string by bytes
can cut through multi-byte UTF-8 sequences, leading to invalid sequences.
To avoid this, strings should be sliced based on characters rather than bytes.
Fixes issue 4886
Samantaz Fox
97895a491a