v1.6.7

• Recognize the little-known cmd /r as a synonym for cmd /c so that Clink can optimize and skip injecting into a cmd /r process.
• Fixed displaying descriptions when they're left-justified (regression introduced in v1.6.6).
• Fixed argmatcher:chaincommand("run") to not find argmatchers for builtin CMD command names (since CMD doesn't get invoked in that case, so it won't get interpreted as a CMD command).
• Fixed argmatcher:chaincommand() to find an argmatcher for a builtin CMD command even if a directory exists with the same name (since CMD interprets that case as a CMD command).
• Fixed argmatcher:chaincommand("cmd") so when exec.aliases is enabled it can include aliases as completions.
• Fixed argmatcher:addarg({loopchars="+", etcetc}) so that -Q:+x still gets parsed into two input words -Q: and +x.
• Fixed to parse foo^ bar as two words "foo" and "bar".
• Fixed to recognize ^echo (etc) as a builtin CMD command name despite embedded ^ characters.
• Fixed #570; fixed #569 more thoroughly, and cd /d cannot be used anywhere because it also requires command extensions.