revset: strip off "literal:" prefix from bookmark not found error This is what branch() and tag() do.

revset: do not fall through to revspec for literal: branch (issue4838) If "literal:" is specified, it must not be a revset expression. It should error out with a better message.

hgweb: ensure both foreground and background colors are specified (issue4872) When users configure the default foreground or background color to non-default (black on white) values, several hgweb styles lack contrast for headers and table row items. This patch fixes that by ensuring that where either foreground or background colors are specified, both are specified.

templater: do not pre-evaluate generator keyword at runsymbol (issue4868) It was introduced by e06e9fd2d99f, but the important code was removed by a3c2d9211294. So there was no positive effect other than exhausting memory. The problem spotted by e06e9fd2d99f is that you can't use a generator keyword more than once. For example, in hgweb template, "{child} {child}" doesn't work because the first "{child}" consumes the generator. But as a3c2d9211294 says, the fix was wrong because it could overwrite a callable keyword that returns a generator. Also the fix didn't work for a generator of generator such as "{diff}" keyword. So, the proper fix for that problem would be to not put a generator in a keyword table. Instead, it should be a factory of a generator. Note that this should fix the memory issue in hgweb, but my firefox killed by OOM in place. Be careful to not use a modern web browser to test the issue4868.