The original idea was to have a warning when
use-package-inject-hooks is set to nil however
having a warning in that macro caused too much
negative side effects and also does not cover
all cases.
Therefore it is to be removed.
In my first commit I did not add the warning message properly.
Basically the macro should emit code to create a warning if
the generated code is run and the predicate is not fulfilled.
However in my last commit it did run the code during macro
expansion which would do the testing there which is not
what I wanted.
spacemacs|use-package-add-hook is generating code which
is dependent on use-package-inject-hooks being non-nil.
If this happens now a big warning is written to the log
informing users of a potential issue or problem caused
by their user-config.
