Fuzzy Select: Special characters lead to panic

[deg0nz]

Entering special characters that consist of more than one char (like ä, ö, ü, é, ê, ...) lead to a panic.

This seems to be due to the fact that we use a range in search_term[0..cursor_pos].

I will check, if using Slices fixes the issue.

Edit: also found this while implementing #179

[deg0nz]

I digged into this and it seems to be an inherent property of unicode characters. Characters like ä actually are grapheme clusters and have a length of 3 chars. We need to consider that fact when splitting str.

The Rust standard library explicitly says, that it does not solve the iteration over grapheme clusters.

Since fuzzy-select is behind a feature, I suggest we also include https://crates.io/crates/unicode-segmentation for the fuzzy select feature and split the search term with that crate to support non-ascii characters.

[Araxeus]

This is especially annoying for users that aren't English speakers

For example:
Cyrillic. Hebrew. Chinese, Arabic, etc...