New AssertThatInstanceOf inspection that moves instanceof expressions out of assertThat(). Fixes to documentation.

src/test/resources/inspections/InstanceOf/InstanceOfAfter.java

@@ -0,0 +1,22 @@
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class InstanceOf {
+
+    private void instanceOf() {
+        Boolean object = Boolean.TRUE;
+
+        assertThat(object).isInstanceOf(Boolean.class);
+        assertThat(object).isInstanceOf(Boolean.class);
+        assertThat(object).isInstanceOf(Boolean.class);
+        assertThat(object).isInstanceOf(Boolean.class);
+        assertThat(object).isInstanceOf(Boolean.class);
+
+        assertThat(object).isNotInstanceOf(Boolean.class);
+        assertThat(object).isNotInstanceOf(Boolean.class);
+        assertThat(object).isNotInstanceOf(Boolean.class);
+        assertThat(object).isNotInstanceOf(Boolean.class);
+        assertThat(object).isNotInstanceOf(Boolean.class);
+
+        assertThat(object).as("nah").isNotInstanceOf(Boolean.class);
+    }
+}

src/test/resources/inspections/InstanceOf/InstanceOfBefore.java

@@ -0,0 +1,22 @@
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class InstanceOf {
+
+    private void instanceOf() {
+        Boolean object = Boolean.TRUE;
+
+        assertThat(object instanceof Boolean).isEqualTo(Boolean.TRUE);
+        assertThat(object instanceof Boolean).isEqualTo(true);
+        assertThat(object instanceof Boolean).isNotEqualTo(Boolean.FALSE);
+        assertThat(object instanceof Boolean).isNotEqualTo(false);
+        assertThat(object instanceof Boolean).isTrue();
+
+        assertThat(object instanceof Boolean).isEqualTo(Boolean.FALSE);
+        assertThat(object instanceof Boolean).isEqualTo(false);
+        assertThat(object instanceof Boolean).isNotEqualTo(Boolean.TRUE);
+        assertThat(object instanceof Boolean).isNotEqualTo(true);
+        assertThat(object instanceof Boolean).isFalse();
+
+        assertThat(((object)) instanceof Boolean).as("nah").isEqualTo(true && !true);
+    }
+}