Time Interval Formatting

[oleibman]

Fix #2768. DateFormatter handles only one of six special formats for time intervals [h] [hh] [m] [mm] [s] [ss]. This PR extends support to the rest. There should be no more than one of these in any format string. Although it certainly could make sense to treat [d] [dd] in the same manner, Excel does not seem to support those.

Interesting observations - hours and minutes are truncated (presumably because they may be followed by minutes and seconds), but seconds are rounded. Also, there are some floating point issues, which fortunately showed up for the example in the original issue. There, the time interval was 1.15, which should evaluate to a minutes value of 1656 (as it does in Excel). However, on my system it evaluated to 1655 because of a rounding error in the 13th decimal place. To overcome this, values are rounded to 10 decimal places before truncating.

This is:

- [x] a bugfix
- [ ] a new feature
- [ ] refactoring
- [ ] additional unit tests

Checklist:

• Changes are covered by unit tests
  • Changes are covered by existing unit tests
  • New unit tests have been added
• Code style is respected
• Commit message explains why the change is made (see https://github.com/erlang/otp/wiki/Writing-good-commit-messages)
• CHANGELOG.md contains a short summary of the change
• Documentation is updated as necessary

Why this change is needed?

Provide an explanation of why this change is needed, with links to any Issues (if appropriate).
If this is a bugfix or a new feature, and there are no existing Issues, then please also create an issue that will make it easier to track progress with this PR.

[MarkBaker]

While I'm reminded: callbacks in the format ['self', 'escapeQuotesCallback'] are being deprecated in PHP 8.2; the valid replacement format is [self::class, 'escapeQuotesCallback']

[MarkBaker]

Also worth noting:

$format = preg_replace_callback('/"(.*)"/U', $callback, $format);

can return null or a string; and phpstan may subsequently complain when that value is passed as an argument to another function. Rather than doing anotherFunction($format ?? ''), it's probably better to enforce the string earlier with an explicit cast of the return from preg_replace_callback()

$format = (string) preg_replace_callback('/"(.*)"/U', $callback, $format);

[oleibman]

Changes applied in latest commit. It looks like there are only 2 other places in PhpSpreadsheet where 'self' is used.