Add testing for HtmlElementCreator and fix ...args calls

All args passthrough class where missing the leading "..."

Added Testing to HtmlElementCreator

src/utils.mjs

@@ -197,7 +197,7 @@ function roundPrecision(number, prec) // eslint-disable-line no-unused-vars
 // @ts-ignore
 function formatString(string, ...args) // eslint-disable-line no-unused-vars
 {
-	return _formatString(string, args);
+	return _formatString(string, ...args);
 }
 
 /**
@@ -775,7 +775,7 @@ function ael(base, attach, id = '') // eslint-disable-line no-unused-vars
 // @ts-ignore
 function aelx(base, ...attach) // eslint-disable-line no-unused-vars
 {
-	return hec.aelx(base, attach);
+	return hec.aelx(base, ...attach);
 }
 
 /**