Fix right-click accidentally triggering chording

package.json

@@ -1,6 +1,6 @@
 {
     "name": "minesweeper",
-    "version": "0.86.4",
+    "version": "0.86.5",
     "description": "Just Minesweeper!",
     "author": "Florine W. Dekker",
     "browser": "dist/bundle.js",

src/main/js/Game.ts

@@ -384,7 +384,7 @@ export class Game {
                         case 2:
                             if (!this.rightDown) break;
 
-                            if (!this.bothHeld && !this.leftDown)
+                            if (this.bothHeld && !this.leftDown)
                                 this.field.chord(coords);
 
                             this.rightDown = false;