Don't suggest -Wno-deferred-out-of-scope-variables

[jeukshi]

Fixes #4440

This does the trick, I don't get the code action on my local branch.

~I'm just unsure if those tests do what they are supposed to do.~

~If I disable blacklist~

warningBlacklist :: [T.Text]
warningBlacklist =
  -- Don't suggest disabling type errors as a solution to all type errors.
  [ --"deferred-type-errors"
  -- Don't suggest disabling out of scope errors as a solution to all out of scope errors.
  --, "deferred-out-of-scope-variables"
  ]

~they do pass on my machine. The list is empty anyway, also in the case of deferred-type-errors. But that is beyond my current knowledge of the codebase.~

Edit: fixed.