The question How to fully discharge supercapacitor? was answered by showing the user that they had made a calculation error.
Should there be a "caused by a typo or calculation error" close reason?
It's common that there incorrect items or statements in the question, they are asking a question because they aren't certain. There is no need to close questions because they are technically incorrect, unless the error is something very trivial and localized, with no interest to future readers. For example, Stack Overflow closes questions that can be answered by fixing a simple typo, like a stray semicolon in source code.
I think a question based on typos or silly misunderstandings should be closed here on EE as well. Like for example: "What is the current flowing through R1 in this schematic? It burned up - see picture - and I'm trying to figure out why". Then someone notes: "That's not R1, the silk screen says R10". Such a question can't be answered but needs clarification by the OP - close as unclear until fixed.
No, the best course of action is to downvote a post if you feel it isn't right (I personally see no reason for a downvote on this question). Close reasons are network wide (most of them) and require a network wide change, it is unlikely that any one site will be able to change the close reasons.