Reduce the scope of slaveCost and make it const

src/markets/specialSlave.js

@@ -7,7 +7,6 @@ App.Markets.specialSlave = function() {
 	let p;
 	const heroSlaves = App.Utils.buildHeroArray();
 	let slave;
-	let slaveCost;
 	let selectedID;
 
 	// Element to show the entire catalog when selected, or a blurb for a random slave
@@ -88,7 +87,7 @@ App.Markets.specialSlave = function() {
 		const el = new DocumentFragment();
 		let p;
 		const {his} = getPronouns(slave);
-		slaveCost = heroSlaveCost(slave, 20000);
+		const slaveCost = heroSlaveCost(slave, 20000);
 		App.UI.DOM.appendNewElement("p", el, App.Desc.longSlave(slave, {market: "generic"}));
 
 		p = document.createElement("p");