qnew: use "editor" argument of "commit()" instead of explicit "ui.edit()" Before this patch, "hg qnew" invokes "ui.edit()" explicitly to get commit message edited manually. This requires explicit "localrepository.savecommitmessage()" invocation to save edited commit message into ".hg/last-message.txt", because unexpected exception raising may abort command execution before saving it in "localrepository.commit()". This patch uses "editor" argument of "localrepository.commit()" instead of explicit "ui.edit()" invocation for "hg qnew". "localrepository.commit()" will invoke "desceditor()" function newly added by this patch, and save edited commit message into ".hg/last-message.txt" automatically. This patch passes not "editor" but "desceditor" to "commit()", because "hg qnew" requires editor function to return edited message if not empty, or default message otherwise. This patch applies "rstrip()" on "defaultmsg" at comparison between "nctx.description()" and "defaultmsg", because the former should be stripped by "changelog.stripdesc()" and the latter may have tail white spaces inherited from "patchfn".