unify some line names

[matthiaskrgr]

Right now we have lints that start with unneeded_, needless_, unused_ and redundant_

I feel like most of these prefixes are trying to express the same so perhaps we could make this more consistent somehow?

[flip1995]

cc #2845 This was already mentioned there. When we do this, we should address most of what is raised in that issue, so we don't have multiple mass rename waves, raising clippy::unknown_clippy_lints warnings. (is this lint auto applicable? 🤔 )

[phansch]

Going to close this in favor of #2845