PHP date formats page has moved, update links in description

[jenlampton]

Description of the bug

There are a few places where we link to the date formats page for PHP, but it's changed.

Old link destination: https://www.php.net/manual/en/function.date.php
Recommended new link: https://www.php.net/manual/en/datetime.formats.php#datetime.formats.time

Steps To Reproduce

To reproduce the behavior:

1. Go to recent log messages at admin/config/development/logging
2. Click on PHP manual(link is external)
3. Find nothing useful about how to format your date

This probably needs to be upated on the date formats page as well, and anywhere else we may have had the old link in the code.

Additional information

Add any other information that could help, such as:

• Backdrop CMS version:
• Web server and its version:
• PHP version:
• Database sever (MySQL or MariaDB?) and its version:
• Operating System and its version:
• Browser(s) and their versions:

[indigoxela]

@jenlampton I belief, this has already been fixed in #4536 (several years ago).

I can't find any url like php.net/manual/en/function.date.php throughout core, so I don't know where your own install should get them from, if not hopelessly outdated (older than 1.16.3).