(Javadoc) Fix return tag for throwableOf*() methods #518.
(Javadoc) Fix return tag for throwableOf*() methods #518.

MarkDacek/commons-lang,britter/commons-lang,britter/commons-lang,MarkDacek/commons-lang,apache/commons-lang,britter/commons-lang,apache/commons-lang,apache/commons-lang,MarkDacek/commons-lang