Remove cell merge/unmerge from menu

scripts/catc.js

@@ -436,9 +436,8 @@ class Editor {
 				'better-table': {
 					operationMenu: {
 						items: {
-							unmergeCells: {
-								text: 'Another unmerge cells name'
-							}
+							mergeCells: false,
+							unmergeCells: false
 						}
 					}
 				},