List items that contain sub-items followed by text are not rendered properly

Some investigation:

• WikiModel doesn't support ending nested lists. It only supports ending the whole list. List handling seems to be deep in some list balancing code, I didn't dig deep enough if we could somehow force it to produce the end event early but I have the impression that this could be possible. In theory we would also want to wrap the whole content in a group syntax but that's impossible to detect without a heavy lookahead that we currently don't have.
• I would be quite surprised if the XWiki syntax renderer handled this situation correctly even with a correct XDOM unless the XDOM would wrap the content after the nested list in a paragraph but I didn't test that part yet.

A rendering test to reproduce at least the parser side:

.#-----------------------------------------------------
.inputexpect|xhtml/1.0
.#-----------------------------------------------------
<ul><li>foo<ul><li>bar</li></ul>after</li></ul>
.#-----------------------------------------------------
.expect|event/1.0
.#-----------------------------------------------------
beginDocument
beginList [BULLETED]
beginListItem
onWord [foo]
beginList [BULLETED]
beginListItem
onWord [bar]
endListItem
endList [BULLETED]
onWord [after]
endListItem
endList [BULLETED]
endDocument