hgweb: generate last change date for an empty atom-bookmarks feed (issue5022) RFC 4287 states that atom feeds must have an <updated> element, so let's add one even when repo doesn't have a single bookmark.

hgweb: sort bookmarks in revlog order of their nodes Changes, branches and tags are already in revlog order on /summary, /branches and /tags, let's now make bookmarks be sorted by the same principle. It's more helpful to show more "recent" bookmarks on top. This will affect /bookmarks page in all styles, including atom, rss and raw, and also /summary page. Bookmarks are sorted using a (revision number, bookmark name) tuple.

hgweb: sort bookmarks early Let's do the same thing that /tags page does. It gets sorted tags and then if it needs the latest only, it just slices the first item from the list. Since it's a slice and not a min(), it doesn't throw an exception if the list is empty. This fixes HTTP 500 error from issue5022.

hgweb: add parents to json-log (issue5074) Entries prepared in webutil.changelistentry() skip showing parents in the trivial case when there's only one parent and it's the previous revision. This doesn't work well for the json-log template, which is supposed to just dump raw data in an easy-to-parse format, so let's provide all parents as another keyword: allparents. Using a lambda function here means that the performance of templates that don't use allparents won't be affected (see 41957e50e109).

revset: make _parsealiasdecl() simply return the original parsed tree It wasn't necessary to reconstruct the same tuple.

revset: inline isvalidfunc(), getfuncname() and getfuncargs() See the previous commit for why. These functions are also trivial.

revset: inline isvalidsymbol() and getsymbol() into _parsealiasdecl() Since I'm going to extract a common alias parser, I want to eliminate dependencies to the revset parsing rules. These functions are trivial, so we can go without them.

revset: remove redundant checks for parsed tree of alias If tree is a tuple, it must have at least one element. Also the length of node tuple is guaranteed by the syntax elements. (e.g. 'func' must have 3 items.) This change will help inlining these trivial functions in future patches.