Add an incompleteTypes > implicitGenerics fixer for functions

[JoshuaKGoldberg]

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🚀 Feature Request

React's useState is a common example of this, but generally some functions may need a generic explicitly stated:

const [name, useName] = useState<string>();

Existing Behavior

No such considerations exist in TypeStat.

Change Proposal

Similar to class and variable implicit generic inferences, there should also be one for functions.