auto numbering paragraph need a rPr node to adjust font/size

[ghmole]

if a paragraph is auto numbering, a subnode '<w:numPr>' will be create under the node '<w:pPr>', also another subnode '<w:rPr>' need be create to save the auto numbering's font/size, so if the '<w:pPr>' node haven't this subnode, you can't modify the auto numbering's font attributes, the different font size will display on same line.

[scanny]

A w:pPr element is added to a w:p element when necessary to add settings, in particular .alignment, and .style. This is done using CT_P.get_or_add_pPr() -> CT_PPr. It always returns the w:pPr element, adding it only when necessary. You can use it like this:

pPr = paragraph._p.get_or_add_pPr()