Shouldn't allow binding to globals referenced in script

[Conduitry]

<script>
	console.log(foo);
</script>

<input bind:value={foo}>

Binding to foo - a global - shouldn't be allowed, but the compiler allows this if it has been referenced in the script.

[Conduitry]

Somewhat relatedly:

<script>
	console.log(foo);
</script>

{foo}

Since foo is referenced in the script, this does not produce a warning about {foo} in the template. I'm not sure whether this should also be considered a bug.

[thgh]

I'm not sure if Svelte should allow access to globals in templates/components.
Related: #2139 (comment)

I would make it explicit:

<script>
  let foo = window.foo
  console.log(foo);
</script>

{foo}