formatter: render template specified by templatespec tuple

formatter: put topic in templatespec tuple This will allow us to change the initial template reference depending on how the template is looked up. For example, -Tdefault => (ref='changeset', tmpl=None, mapfile='map-cmdline.default') -T'{rev}' => (ref='', tmpl='{rev}', mapfile=None) A literal template given by -T option will be stored as an unnamed template, which will free up the template namespace so that we can load named templates from [templates] section of user config.

cmdutil: pass templatespec tuple directly to changeset_templater (API) A fewer number of arguments should be better.

formatter: wrap (tmpl, mapfile) by named tuple I'm going to add more options to the templatespec tuple. cmdutil.logtemplatespec() is just an alias now, but it will be changed to a factory function later.

cmdutil: factor out helper to create changeset_templater with literal template changeset_templater has lots of arguments, but most callers only need to specify a literal template 'tmpl'. "hg debugtemplate" has no diff option, which means 'opts' were effectively {}, so dropped opts.

test-dirstate-race: stabilize for Windows Without quoting, the output after "custom merge tool" in the next test is an abort trying to open "C:UsersMattAppData..."

formatter: document lookuptemplate()

cmdutil: rename gettemplate() to _lookuplogtemplate() This function is only useful when processing log options.

formatter: inline gettemplater() Since it's highly use-case dependent how template should be looked up, gettemplater() function isn't useful. Keeping it would introduce another bug I've made and fixed earlier in this series.

formatter: factor out function to create templater from literal or map file (tmpl, mapfile) will be packed into a named tuple later.