* We don't need it anywhere in JS, since we're not sending that HTML
to Parsoid.
* We only need it on the nodes directly containing our reply lines in
PHP, not all over the place.
Change-Id: I0a04388225f32654dda2f599442cd27a303b5d0a
Sequential numbers aren't great because they change when an earlier
comment is archived. Parent comment/heading IDs should change less
often.
This also makes much more sense for disambiguating subsections,
e.g. a dozen identical ===Votes=== sections for a dozen proposals.
Bug: T264478
Change-Id: I466454984fd919ebef35f2b37ddb5d86dc842996
Previously, only comments could have IDs, because we only needed IDs
for replying. But we might also use them for notifications soon.
Bug: T264478
Change-Id: I1bcad02bf17ab54bc5028a959543c10f0430836b
Previously we preferred that, but used '*' (<ul><li>) when the parent
comment or the previous reply also used it.
Bug: T252708
Change-Id: I3abf606da6693905764f1be745fad999fdf57fbe
