tests: show how `hg split` can put color codes in commit template With D9255, I made it so `hg split` respects the `commmand-templates.oneline-summary` config. I don't think I realized that the output I modified was being put in a commit message template. The result was that if you have coloring enabled, you get colors in the commit template. This patch show that. The test is unfortunately pretty verbose (like most other `hg split` tests) and shows a bunch of irrelevant "color codes" (templater labels). Differential Revision: https://phab.mercurial-scm.org/D9321