SI-7767 avoid rejecting Scaladoc comments in early initializers

review by @retronym
SI-7767 Test case for Scaladoc on early initializers
Merge pull request #1 from retronym/ticket/7767-test

Test case for SI-7767
Merge pull request #2922 from huitseeker/issue/7767

SI-7767 avoid rejecting Scaladoc comments in early initializers