• "indent" for cases where the only purpose was to indent things
• "blockquote" where you want an actual block quote in a wiki doc and thus can't use a "blockquote" element due to the historical misuse of this tag, preventing us from doing the same for it as we do for MD
• "sidebar" when the reason you wanted an indented paragraph was to create a sidebar; this is styled much like a blockquote in MD (or the new "blockquote" class in wiki docs) but floats to the right.

Using all three of these in the remaining www/ docs that still used explicit "blockquote" tags.

(If you're wondering why the prior commit claims to have dealt with all of these tags when this commit belies that, it's because this work was done en masse, then split up into two related commits to keep the commit messages more on-point. It was easier to commit these two chunks of work in this order. It would have required a complicated dance with the stash to commit them in the more logical order.) file: [bc4386e67b] check-in: [56c7c2cb13] user: wyoung branch: inskinerator-modern-backport, size: 6339

• in Markdown nested lists, where blank lines should render the list items as separate paragraphs just as at the list's top level; since it does not, if you want a line break, you either have to wrap the item in "p" tags or do the double-br hack.
• in Wiki where blank lines within a list give you a separate list in the HTML output; this is fine for bullet lists, but with numbered lists it causes the numbering to restart unless you do the same sort of manual HTML workaround as with the prior item
• in plain HTML docs and wiki docs between "nowiki" tags

In many places, this cleanup gets rid of pointless stray "p" tags, placating HTML verifiers. file: [2e692648ea] check-in: [1fd407f61a] user: wyoung branch: trunk, size: 6418