compiler: add $$self to reserved_keywords

src/compiler/compile/utils/reserved_keywords.ts

@@ -1,4 +1,4 @@
-export const reserved_keywords = new Set(["$$props", "$$restProps"]);
+export const reserved_keywords = new Set(["$$props", "$$restProps", "$$self"]);
 
 export function is_reserved_keyword(name) {
 	return reserved_keywords.has(name);