Add option to pass functions as values for TSX HTML element attributes:
```
lang=ts
const html = <button onclick={ ( {alert} )=>{ alert("clicked!") } }></button>;
```
The functions should be stringified with `fn.toString()` - but only the body of the function should be passed to the resulting HTML. The `( {alert} ) => {`) and the closing `}` should be omitted. This removal should work for:
- anonymous functions - `function({alert}){}`
- named functions - `function test({alert}){}`
- arrow functions - `()=>console.log("hehe")`
- arrow functions with brackets - `()=>{console.log("hehe")}`
Typescript should be informed about the types for the argument to that function - it should be an object that contains the global DOM variables, like `document`, `alert`, etc.