Normative: Added support for sentence break suppressions to Intl.Segmenter

[ben-allen]

fix #580

Added support for u-ss to Intl.Segmenter

[sffc]

Needs feedback from @Constellation. Also, @FrankYFTang pointed out that changes are needed in Appendix A/B.

https://github.com/tc39/ecma402/blob/master/meetings/notes-2023-06-01.md#normative-added-support-for-sentence-break-suppressions-to-intlsegmenter-783

[FrankYFTang]

Sorry, I think we need additional changes that I forget to mention in TG2.

A. We should also change 14.1.1 Intl.Locale ( tag [ , options ] ) https://tc39.es/ecma402/#sec-Intl.Locale to take option "sentenceBreakSuppressions"

B. The internal slot of Locale should also include "ss" https://tc39.es/ecma402/#sec-intl.locale-internal-slots

C. We should also add a getter in section 14.3 https://tc39.es/ecma402/#sec-properties-of-intl-locale-prototype-object 14.3.X get Intl.Locale.prototype.sentenceBreakSuppressions

which return either "none" (default) or "standard")

[ben-allen]

Updated to incorporate required changes to Intl.Locale & include a note in Annex A. Unclear on needed changes to Annex B.

[sffc]

Note: @dminor would like to wait until ICU4X supports this feature before merging this PR.

https://github.com/unicode-org/icu4x/issues/3927

[sffc]

The PR is not mergeable any more in its current form, so I'll close it, and we can make a new one once the ICU4X issue is resolved.