...in numbering.xml. This caused pandoc-produced docx files to
be uneditable using Word Online.
The problem was that recent versions of reference.docx include
samples of various kinds of text, including lists. The
numering elements for these were getting copied over to
the new docx, where they clashed with the autogenerated
elements produced by pandoc. This didn't confuse Desktop
Word, but it did confuse Word Online.
Closes#5358.
