Repro

{"rules": {"@typescript-eslint/ban-types": ["error"]  }}

functionisFunction(value:any):value isFunction{returntypeofvalue==='function';}

Expected Result

The tslint:recommended ruleset for ban-types includes Function
https://github.com/palantir/tslint/blob/master/src/configs/recommended.ts#L23

So I would expect it to be the same in @typescript-eslint/recommended.
I was unable to find any issues about it being intentionally removed.

Actual Result

Function type usage is not banned

Additional Info

To match TSLint I have to do this

"@typescript-eslint/ban-types": ["error",  {"types": {"Function": {"message":"Prefer a specific function type, like `() => void`."       }     }  }]

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