AnnotationRule: don't report if a comment is placed after the last annotation

[t-kameyama]

Fixes #736

[shashachu]

@t-kameyama thanks for the PR. Can you confirm that

@Annotation1 // comment 1
@Annotation2
class MyClass {
}

passes with no errors as well? I believe it should based on the bug report but I'd like to confirm. Apologies if this is already covered in test cases.

[t-kameyama]

Added a test.

[shashachu]

thank you!