Ellipsis: avoid Unicode character truncation

[ccoVeille]

While you are working on Ellipsis, please look at the code behavior.

I doubt the code does what is expected with a Unicode character like 🧜‍♂️ by truncating to Len 1

[samber]

Yes, I confirm the bug:

is.Equal("1🧜‍♂️234", lo.Ellipsis("1🧜‍♂️234", 5))
is.Equal("1🧜‍♂️2...", lo.Ellipsis("1🧜‍♂️234", 6))

[yasuaki640]

This bug could be fixed by counting the string grapheme cluster at github.com/rivo/uniseg .

If this policy is acceptable, I'll work on a PR for the fix!

[samber]

Sure.

Please do not import dependency. I keep this repo as lightweight as possible.
A little copy is sometimes better than a dependency.