ext/intl: Add DECIMAL_COMPACT_SHORT and DECIMAL_COMPACT_LONG for NumberFormatter

[BogdanUngureanu]

This PR introduces two new constants, DECIMAL_COMPACT_SHORT and DECIMAL_COMPACT_LONG, in the NumberFormatter class. These constants are mapped to ICU’s UNUM_DECIMAL_COMPACT_SHORT and UNUM_DECIMAL_COMPACT_LONG.

Although ICU has supported these since version 57, they were not previously exposed in PHP's NumberFormatter class. This update addresses that by adding them.

[devnexen]

Nice ! looks good in first glance I ll go back at it shortly.

[BogdanUngureanu]

Awesome, thanks for the fast response! For the record, this has been working since PHP 5.5 with regular int values (https://3v4l.org/suSMd), but we don't expose it in the docs and this class.

I came across it on stackoverflow where someone was using NumberFormatter::PADDING_POSITION attribute, which coincidentally has the same int value as the formatter.