Support for Unicode Emoji Sets (UTS#51)

[cometkim]

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/unicodeSets
https://www.unicode.org/reports/tr51/#Emoji_Sets

Technically this isn't part of the Unicode Segmentation, but examining the sequence of a specific emoji segment is one of the essential combinations.

for example to resolve matrix-org/matrix-react-sdk#12582

[cometkim]

New matcher APIs to unicode-segmenter/emoji

• isBasicEmoji -> \p{Basic_Emoji}
• isRGIEmoji -> \p{RGI_Emoji}

It will do #40 first as this needs to script change.

[cometkim]

This is out-of-scope of this library due to it's different specification and behavior

I will move this work to another library