Implements a Warning when a :FOR identifier is also mentioned on the :NEEDS

[Lisias]

It was (finally) realized that :NEEDS doesn't completely inhibits :FOR, as it creates an identifier in the tagList even when :NEEDS is not satisfied.

This leaded to confusion more than one time, being one of oldest I found this one, from 2015:

https://github.com/ferram4/Ferram-Aerospace-Research/blame/787a30bc9deab0bde87591f0cc973ec3b0dd2de9/GameData/FerramAerospaceResearch/FerramAerospaceResearch.cfg#L303

It's subtle, but this patch in special does not cause trouble because its :FOR would unconditionally create an entry on the tagList for an add'on's identifier that already exists due the directory name having the same name, so no harm is done.

But exactly by being subtle, some people didn't grasped this counter-intuitive behaviour - what can lead to undesired collateral effects on patches that aims to be applied to an specific before anyone else using :AFTER, but not before anyone using :BEFORE, a use case where using :FOR is tempting.

This pull requests add's a Warning when it detects a :NEEDS using the same name used on :FOR, and I expect it to help prevent some unintended borkage on the field.

[Lisias]

Not every occurrence of :FOR[foo]:NEEDS[foo] is going to cause damage. I had an idea to prevent them from being flagged as problems, what would surely cause some friction.

I'm testing the solution, and will add a commit with it once it's proven to work.