add ListAttributes support for BulletList

[ilcpm]

(this issue is copied from jgm/pandoc#9480)

since we have ListAttributes for OrderedList:

OrderedList ListAttributes [[Block]]
type ListAttributes = (Int, ListNumberStyle, ListNumberDelim)

so why not add ListAttributes for BulletList? the api of BulletList is just barely like:

BulletList [[Block]]

it will be great to add the attribute ListNumberStyle so the <ul> tag can be set to <ul style="list-style-type: circle;">

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in my project, I want to distinguish between - list and * list, so I can set different style on them, but I can't do that now.