Quick info for parameter redundantly shows @param tag

**TypeScript Version:** 3.1.0-dev.20180830 **Code** ```ts /** * @param p * Once upon a time there was a parameter named p. * P lived in a function called f. * Then a big bad wolf came and blew f down. */ function f(p: number): void {} ``` **Expected behavior:** Documentation for `p` is shown only once. **Actual behavior:** Documentation is shown twice -- once as the normal documentation (good), once as documentation for the `@param` tag which is redundant since we took the documentation from there. This doubles the size of the quick info.