This required two changes in parallel.
As a first and obvious step it removes a check that skipped emptys
lines during documentation loading, but it was also necessary to
refactore the `get_comment_lines()` utility method as a second step.
This second refactoring was necessary as each line in a doc comment
is trimmed and transformed in its own doc attribute. The attribute
of an empty line therefore contains an empty string as value. If we
now call `lines()` on such an empty string we end up with an empty
iterator as the method is internally configured to ignore trailing
empty lines.