Merge branch 'ac/auto-comment-char-fix'

"git commit" that concludes a conflicted merge failed to notice and remove existing comment added automatically (like "# Conflicts:") when the core.commentstring is set to 'auto'. * ac/auto-comment-char-fix: config: set comment_line_str to "#" when core.commentChar=auto commit: avoid scanning trailing comments when 'core.commentChar' is "auto"