Treat \u279C arrow as ambiguous width char (like emoji)

Fixes #974

src/renderer/ForegroundRenderLayer.ts

@@ -159,6 +159,11 @@ export class ForegroundRenderLayer extends BaseRenderLayer {
    * @param char The character to search.
    */
   private _isEmoji(char: string): boolean {
+    // Check special ambiguous width characters
+    if (char === '➜') {
+      return true;
+    }
+    // Check emoji unicode range
     return char.search(/([\uD800-\uDBFF][\uDC00-\uDFFF])/g) >= 0;
   }