run-tests: restrict the test cases allowed characters Most test cases in core and in extension only use `A-Za-z0-9-` but a few tests in extensions also have a `.` in their test cases names. Also add a `_` to allow all kind of case naming format. Differential Revision: https://phab.mercurial-scm.org/D3721

templater: abstract truth testing to fix {if(list_of_empty_strings)} Non-empty list should always be True even if it's stringified to ''. Spotted by Martin von Zweigbergk.

show: stringify filtered list of tags before testing emptiness `names % "{ifeq(name, 'tip', '', name)}"}"` may return [''], which shouldn't be falsy, but it is thanks to a templater bug. This patch converts [''] to '' before testing truthness.

templatefilters: deprecate hgdate as {date|hgdate} is the default format

templater: make date wrapper support dot/map operations No idea if it will be useful, but it just works.

templater: introduce a wrapper for date tuple (BC) Strictly speaking, this is BC, but I believe the original string format (str(float(unixtime)) + str(int(tzoffset))) was just plain wrong.

templater: promote tomap() to an interface type I originally considered merging tomap() with itermaps()/getmember(), but decided to not. We might want to add support for chained map operations (e.g. {foo % func() % ...}), where func() will return a mappable object, and 'foo % func()' will be a mappedgenerator of mappable objects.

templater: rename mappable to hybriditem as it is the primary use case This frees up the name 'mappable' for new interface type.

serve: do not daemonize by default by --print-url Per discussion in D3649, -d/--daemon should be explicitly specified to avoid surprising result. Differential Revision: https://phab.mercurial-scm.org/D3703

mercurial: add .t files to .editorconfig The notable entry here prevents the stripping of trailing whitespace, which is important in .t tests. Differential Revision: https://phab.mercurial-scm.org/D3702