9183.md

Adjacent "Source Code" paragraphs become one code block with `+styles`,
as they do without it:
```
% pandoc -f docx+styles -t native command/9183.docx
^D
[ Div
    ( "" , [] , [ ( "custom-style" , "Source Code" ) ] )
    [ CodeBlock ( "" , [] , [] ) "x = 1\ny = x + 1" ]
]
```