add Moodle 4.4 hooks

[usqfowlerj]

This ought to be what's needed to fix issue #84 with Moodle 4.4+ superseding the 'before_standard_html_head' and 'before_http_headers' plugin callbacks.

[usqfowlerj]

What's the strategy for situations like this, where the failure happens in the lint check on a PHP and Moodle version the code will never run under anyway?

[danmarsden]

thanks @usqfowlerj - usually we generate a new branch, which I'm leaning towards doing here with a new 4.4 branch and we could drop the deprecated before_standard_html() code completely at the same time....

[bwalkerl]

Thanks @usqfowlerj

I've had some luck getting around that issue for a similar hook by including it in a use statement, which shortens the line enough to meet the coding guidelines, i.e. https://github.com/catalyst/moodle-local_envbar/pull/210/files

I personally don't think we need a new 4.4 branch for this particular change as there's a clear workaround, and the hooks will work cleanly on all supported versions. Though it would be worth adding a note mentioning the deprecation to the old functions in lib.php, similar to what has been done in the linked example above.

If you can get that sorted and rebase onto MOODLE_401_STABLE we should be able to look at merging this in.

[usqfowlerj]

I believe it should all be in order as suggested.