Fix IEnumerable.Union() result being discarded in ContentByQuerySearchTransformator

[jackpoz]

This PR fixes a typo where the result of IEnumerable.Union() is discarded. The author probably assumed this LINQ method was going to modify the collection itself but it actually returns a new collection.

In this particular case the first collection is always empty, so it's enough to just assign the variable to the second collection.

List<ContentType> cts = new List<ContentType>();

Another way could be to assign the result of Union() to the variable cts .

Please note that I'm not familiar with how this part of the code is used or how to test it but it looks like a small change only.

[jansenbe]

Good catch, thanks for sharing @jackpoz