fix #3232

[jeffreyniu]

I made a fix myself, please review and merge.

[kenz-gelsoft]

I confirmed this change won't break the Japanese input by testing following examples with Pop!_OS 24.04, macOS and Windows:

• todo
• styling (originally reported in text_input throws error when enter 3 Chinese words #3232)
• combo_box
• on macOS, following examples don't work with Kanji(Hanji) characters correctly with or without this change (separate problem)
  • editor
  • markdown

(EDIT: this change is OK on Windows too. I experienced link.exe error, that was because I forgotten installing required Windows SDK components.)

[kenz-gelsoft]

Here, the input_method::Preedit.selection value comes from winit's Preedit event.

https://docs.rs/winit/latest/winit/event/enum.Ime.html#variant.Preedit

The winit's Preedit event doesn't specify negative Range specifically, and

https://doc.rust-lang.org/std/ops/struct.Range.html

It is empty if start >= end.

Range document says negative Range means the range is empty, so this change looks correct for me.

[kenz-gelsoft]

I commented this PR as a contributor in this area to help the library author understanding this change.

As I don't have merge right, please wait for the devs reviewing your change.

[jeffreyniu]

thanks, it may also needs merge to 0.14 release and build out a package.