store comment's ContentRange in InsertCommentEdit

When a comment is deleted, it gets dissociated from the document. While
it can still be referenced by an InsertCommentEdit, it is useless for
undo/redo, because its ContentRange gets lost when it is dissociated.
Hence the ContentRange must also be stored in InsertCommentEdit.

Signed-off-by: Florian Thienel <florian@thienel.org>
4 files changed