filelog: add the ability to report the user facing name This will be used by lfs, but is probably generally useful. There are various bits of code that reverse engineer this from the index or data file names, but it seems better to just store it. Especially if there's experimenting with backing storage other than revlog.

hgweb: make different kinds of commits look differently on /graph Regular hg log -G uses different symbols for some graph nodes, such as commits that close branches and hidden commits. It also marks the currently checked out commit with "@". Since hg serve is sometimes used/recommended as a more visual alternative to CLI, it makes sense to port these features to hgweb. "graphnode" includes the style of a particular node and also if it's currently checked out or not, both at the same time. This is different from hg log -G (which uses templatekw.showgraphnode), where there's only place for one character, but hgweb doesn't have this limitation, since it uses <canvas> and not plain text. I'm using one string of 1 or 2 characters in this patch, it's not the most self-explanatory format, but it's concise, uses the same characters as hg log -G, and is internal to hgweb (i.e. not used for json-graph). I'm more or less fine with how things look visually, but there's still room for improvement. Feel free to criticise or point me to good-looking graphs of this kind for inspiration.