Returns true if the given expression contains a cdot for the given HygieneInfo name.
If no HygieneInfo name is given, then returns true if there is any cdot.
The search is delimited by cdot binders (any syntax satisfying isCDotBinderKind).
If the term contains any cdots that match the given HygieneInfo name (see isCDotForInfo),
then returns some with the expanded syntax, otherwise returns none.
Examples:
· + 1=>fun x => x + 1f · · b=>fun x1 x2 => f x1 x2 b