stop using the "dark shade" character for standard walls

now uses inverse bullet for sealed walls and full block otherwise

src/mapgen.ts

@@ -100,7 +100,7 @@ class Knife {
           const loc = new Point(x, y);
           out += (() => {
             if (this.#map.get(loc).architecture == Architecture.Wall) {
-              return this.#sealedWalls.get(loc) ? "█" : "▓";
+              return this.#sealedWalls.get(loc) ? "◘" : "█";
             }
             let r = this.#regions.get(loc);
             if(typeof r === "number") {