Generic fix to be same as hamcrest assert signature

generic type fix to be same as hamcrest assertThat(T, Matcher<? super T>) signature

https://github.com/hamcrest/JavaHamcrest/blob/master/hamcrest-core/src/main/java/org/hamcrest/MatcherAssert.java#L11

In this commit https://github.com/hamcrest/JavaHamcrest/commit/a6b00c4aadae733236e481fa747d5223cc7b7a9a#hamcrest-core/src/main/java/org/hamcrest/MatcherAssert.java they change generic same way