Add description to INI mode constants

[haszi]

Adds descriptions to each INI mode constant, copied from their PHP_INI aliases.

These are also on the missing constants list which I'm guessing is because these are in a table instead of a variablelist.

[haszi]

I took another look at the source code and it seems that the PHP_INI_* constants are not even exposed to userland so I removed these as aliases.

Unfortunately it gets worse than this. These non-existent constants are used 730 times in 88 doc files, mostly in the ini.xml files of just about every extension.

I could submit one PR with a huge number of changes but I'm not sure that would be welcome.

[Girgias]

Aaaaaaaaaaaaaaaaaaaaaaaaa

Well this is... unfortunate. However, as those are easily machine fixable I think it should be done, but the commit should have a [skip-revcheck] tag and the same script should be applied to all translations. Might as well also add the missing <constant> tags if possible.

But this should be a separate PR.