Fix rendering issues for emojis that come out as wide chars

The fix is to disallow non-single cell width chars to be overlapping

src/renderer/TextRenderLayer.ts

@@ -183,10 +183,15 @@ export class TextRenderLayer extends BaseRenderLayer {
   }
 
 	/**
-	 * Whether a character is overlapping to the
-	 * next cell.
+	 * Whether a character is overlapping to the next cell.
 	 */
   private _isOverlapping(charData: CharData): boolean {
+    // Only single cell characters can be overlapping, rendering issues can
+    // occur without this check
+    if (charData[CHAR_DATA_WIDTH_INDEX] !== 1) {
+      return false;
+    }
+
     // We assume that any ascii character will not overlap
     const code = charData[CHAR_DATA_CODE_INDEX];
     if (code < 256) {