histedit: use "getcommiteditor()" instead of explicit editor choice for "--continue" This omits (redundant) adding "\n' to "message", because: - empty line is inserted by "commitforceeditor", if editor is invoked - tail white-spaces are stripped at storing into chaneglog, otherwise This patch also enhances "test-histedit-edit.t", because "hg histedit" hasn't been explicitly tested around editor invocation and "--continue" option.

histedit: use "getcommiteditor()" instead of explicit editor choice for "fold" This patch doesn't change any tests like as preceding patches, because editor invocation is already tested in "test-histedit-fold.t".

histedit: use the editor gotten by "getcommiteditor()" for "message" Before this patch, "hg histedit" for "message" uses "ui.edit()" for commit message editing. It shows original commit message, but not detail about the target revision: status of each modified/added/removed files, for example. This patch uses the editor gotten by "getcommiteditor()" instead of "ui.edit()" for "message" In "test-histedit-edit.t", this patch omits "fixbundle" invocation, because it prevents from confirming the "HG: added f" line in commit message by filtering " added " lines. Omiting "fixbundle" invocation causes that the exit code of "hg histedit" appears as one of command line: in this case, "hg histedit" is aborted by (expected) exception raising.