JSDoc optionality should apply from param tags even without a type

[sandersn]

/**
 * @param [a] - you don't have to provide a
 */
function f(a) {
}

Expected signature: f(a?: any): void
Actual signature: f(a: any): void

Note that if we want to retain the UntypedSignatureInJSFile rules, this feature is not needed. However, omitting any untyped argument in JS doesn't make sense for today's uses of JS, and whatever support we have in Corsa should be removed.

[sandersn]

Never mind, I misread the code. When I tested it, optionality applies any time the parameter's type is nil, not the tag's. Which is always the case in correct JS code; and in incorrect code where somebody has put in a type annotation by mistake, I'd expect the semantics to follow TS, plus an error.