Linkifier: underline shift after double width character

[mandel59]

Linkifier doesn't support East Asian Width (wcwidth) yet

Details

• Browser and browser version: any
• OS version: any
• xterm.js version: master (da8151b)

Steps to reproduce

1. Write any URL after East Asian Wide or Fullwidth (a.k.a double width) characters

[Tyriar]

This will involve making Linkifier.ts aware of wide characters similar to how SelectionManager.ts is. This can make the code a lot more complex:

xterm.js/src/SelectionManager.ts

Line 645 in 2cee669

private _getWordAt(coords: [number, number], allowWhitespaceOnlySelection: boolean): IWordPosition {

I wonder if there's a nicer, more generic way to deal with converting between character indexes and column numbers.

[Tyriar]

Works in master 🎉