Handle RecursionAssignment and SwitchCase statement types in CustomJavaDocCommentBuilder

[onewhl]

Description
See PR with introducing custom JavaDoc tags and related issue.

Currently, some of the statement types are not handled in CustomJavaDocCommentBuilder: RecursionAssignment and SwitchCase.

Also, sometimes return statement is a part of other statement, that's why value of returnsFrom tag might be empty in comments. It should be handled as well.

See method CustomJavaDocCommentBuilder#buildCustomJavaDocComment().