[DISCUSSION] Add locale and strength for grapheme functions

Hi, Internals

I changed below the RFC.

• https://wiki.php.net/rfc/grapheme_add_locale_for_case_insensitive
  Pull request is below:
• https://github.com/php/php-src/pull/18792

Change point is below:

• Add a strength for grapheme_* functions
  • Affect to all over the world characters, ex: Ideographic Variation
    Sequence(IVS)
  • Use Collator object const values.

These settings are indeed important for these functions, but I can't get
around the fact that it makes these APIs really cluttered and
complicated — something that many functions in the grapheme_ / intl
extension already suffer from.

Is this API really the best way?

$locale parameter is not change anything. Because I could not find any way.

It seems that I came to a similar conclusion, but locales are much more
complicated than just languageCode_regionCode (for example, see
https://github.com/derickr/php-text/blob/main/tests/text-contains.phpt#L25)

You also don't really need a strength argument, as you can 'encode' that
in the locale name, like: 'nb_NO-u-ks-primary' (I know, it's rather ugly
and the list of options is vast:
https://www.unicode.org/reports/tr35/tr35-collation.html#Common_Settings

cheers,
Derick