Codefix for implicit-any 'this' in function

**TypeScript Version:** 3.1.0-dev.20180813 **Code** ```ts function f() { this.x; } ``` **Expected behavior:** Codefix to add `this: any` as a first parameter to `f`. In situations where `this` is valid outside of the function (e.g. inside a class method), codefix to convert to `const f = () => { ... }` and hoist to the top of its scope if necessary. **Actual behavior:** No codefix.