fix: symbol.hasInstance needed to be static (#136)

esm.min.js

@@ -18,7 +18,7 @@ export const FormData = class FormData {
 constructor(...a){if(a.length)throw new TypeError(`Failed to construct 'FormData': parameter 1 is not of type 'HTMLFormElement'.`)}
 get [t]() {return 'FormData'}
 [i](){return this.entries()}
-[h](o) {return typeof o==='object'&&o[t]==='FormData'&&!m.some(m=>typeof o[m]!='function')}
+static [h](o) {return typeof o==='object'&&o[t]==='FormData'&&!m.some(m=>typeof o[m]!='function')}
 append(...a){x('append',arguments,2);this.#d.push(f(...a))}
 delete(a){x('delete',arguments,1);a+='';this.#d=this.#d.filter(([b])=>b!==a)}
 get(a){x('get',arguments,1);a+='';for(var b=this.#d,l=b.length,c=0;c<l;c++)if(b[c][0]===a)return b[c][1];return null}