When there are multiple \throws entries in a function documentation, the second
and further exception names were omitted from output and a combined description
was associated with the first exception. Fix this by producing separate
paragraphs, one per exception.
Additionally, support free form exception description when the exception type
is specified as "~". In this case, the exception name is not used, and the
entry description is used to initialize the paragraph in the output.
Updated test to verify these changes.
719af2337f