Add missing newline

Author: math-fehr

mlir/unittests/IR/TypeAttrNamesTest.cpp

@@ -87,4 +87,4 @@ TEST(AbstractAttribute, LookupWithString) {
   // Check that lookups of non-existing Attributes returns nullopt.
   // Even if an attribute with the same name exists.
   EXPECT_FALSE(AbstractAttribute::lookup("fake.foo", &ctx).has_value());
-}
+}