cmdutil: look commit template definition up by specified 'editform' Before this patch, '[committemplate] changeset' definition is shared between all actions invoking 'commitforceeditor()'. This prevents template definition from showing action specific messages: for example, 'hg tag --remove' may need specific message to call attention, but showing it may be redundant for other actions. This patch looks commit template definition up by specified 'editform' introduced by prior patches. 'editform' are dot-separated list of names, and treated as hierarchical one.