fix(docx): fix OOXMLValidator error on KeywordTok output

xmllint doesn't warn about this (maybe because the tag is empty?), but
the order doesn't match wml.xsd:
```
    <w:rPr>
      <w:color w:val="007020"/>
      <w:b/>
    </w:rPr>
```

And OOXMLValidatorCLI does warn about it:
```
{
        "Description": "The element has unexpected child element 'http://schemas.openxmlformats.org/wordprocessingml/2006/main:b'.",
        "Path": {
            "NamespacesDefinitions": [
                "xmlns:w=\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\""
            ],
            "Namespaces": {

            },
            "XPath": "/w:styles[1]/w:style[40]/w:rPr[1]",
            "PartUri": "/word/styles.xml"
        },
        "Id": "Sch_UnexpectedElementContentExpectingComplex",
        "ErrorType": "Schema"
    }
```

Signed-off-by: Edwin Török <edwin@etorok.net>

1 files changed, 0 insertions, 0 deletions

diff --git a/test/docx/golden/codeblock.docx b/test/docx/golden/codeblock.docx
index 20440b585..900d29f87 100644
--- a/test/docx/golden/codeblock.docx
+++ b/test/docx/golden/codeblock.docx