Replace AssertionsForClassTypes references with Assertions

[ash211]

What happened?

AssertionsForClassTypes exists as a near-duplicate of the assertj Assertions class. My understanding is that this is due to a deficiency in the Java type system in earlier Java releases, which has now been fixed. Any Java code compiled at Java 11 target or higher should be able to use just the Assertions methods, and can/should ignore AssertionsForClassTypes and also AssertionsForInterfaceTypes.

What did you want to happen?

A migration that can do:

import static org.assertj.core.api.AssertionsForClassTypes.assertThatCode;

->

import static org.assertj.core.api.Assertions.assertThatCode;

and similar for other static imports.

Plus also replace direct references like AssertionsForClassTypes.assertThat(x)... with the statically-imported method from Assertions so we can call assertThat(x)...