Merge branch 'cc/replace'

* cc/replace: t6050: check pushing something based on a replaced commit Documentation: add documentation for "git replace" Add git-replace to .gitignore builtin-replace: use "usage_msg_opt" to give better error messages parse-options: add new function "usage_msg_opt" builtin-replace: teach "git replace" to actually replace Add new "git replace" command environment: add global variable to disable replacement mktag: call "check_sha1_signature" with the replacement sha1 replace_object: add a test case object: call "check_sha1_signature" with the replacement sha1 sha1_file: add a "read_sha1_file_repl" function replace_object: add mechanism to replace objects found in "refs/replace/" refs: add a "for_each_replace_ref" function