[css-display] Position of 'list-item' when serializing <display-listitem>

[Loirooriol]

The summary table in CSS Display says that list-item inline flow serializes to inline list-item.

However, the syntax is

<display-listitem> = list-item && <display-outside>? && [ flow | flow-root ]? ;

Then, according to the "shortest serialization" principle (which is going to be reintroduced in #1564), it should serialize to list-item inline:

Where multiple CSS component values can appear in any order without changing the meaning of the value (typically represented by a double bar || in the value syntax), use the order as given in the syntax.

Therefore, I think either the summary table should say list-item inline or the syntax of <display-listitem> should move the list-item keyword to the end.

[Loirooriol]

@tabatkins Then you should also reorder list-item block flow and list-item inline flow entries in the "Full display" column of the summary table.

[fantasai]

@Loirooriol Done, thanks.