This reverts commit a79cb836, which broke
--with-help builds again, as

  strLine.copy(i->nBegin, i->nEnd-i->nBegin)

in BasicCodeTagger::tagParagraph (helpcompiler/source/BasCodeTagger.cxx) depends
on the invariant that a HighlightPortion does not extend past the source string.

Also, I see no reason for that change, as empty comments are handled just fine
already as demonstrated by the following commit...

Change-Id: I384bae9c4cf6a38d0a0a2832fa15bde82126cace