filemerge: use 'basic' as the default of '[ui] mergemarkers' for safety Before this patch, 'detailed' is used as the default of '[ui] mergemarkers'. This embeds non-ASCII characters in tags, branches, bookmarks, author and/or commit descriptions into merged files in the encoding specified by '--encoding' global option, 'HGENCODING' or other locale setting environment variables. But, if files to be merged use another encoding, this behavior breaks consistency of encoding in merged files. For example, ISO-2022-JP or EUC-JP are sometimes used as the file encoding for Japanese characters, because of historical and/or environmental reasons, even though UTF-8 or Shift-JIS are ordinarily used as the terminal encoding. This can't be resolved automatically, because Mercurial doesn't aware encoding of managed files. This patch uses 'basic' as the default of '[ui] mergemarkers' to avoid embedding encoding sensitive characters for safety. This patch puts '[ui] mergemarkers = detailed' into default hgrc file for tests, to reduce changes for tests in this patch.