set charset variable to "utf-8" when trying to recover a decoding error

lib/single-file/single-file-browser.js

@@ -161,7 +161,8 @@ this.SingleFileBrowser = this.SingleFileBrowser || (() => {
 					return { data: new TextDecoder(charset).decode(buffer), resourceURL, charset };
 				} catch (error) {
 					try {
-						return { data: new TextDecoder("utf-8").decode(buffer), resourceURL, charset };
+						charset = "utf-8";
+						return { data: new TextDecoder(charset).decode(buffer), resourceURL, charset };
 					} catch (error) {
 						return { data: "", resourceURL, charset };
 					}