Clearer wording on Errata openzfs#4

Errata openzfs#4 doesn’t mention a non-destructive way to clear it. This commits fixes openzfs#8682.

Signed-off-by: Justin Scholz <git@justinscholz.de>

cmd/zpool/zpool_main.c

@@ -2572,12 +2572,15 @@ show_import(nvlist_t *config)
 				    "incompatibility\n\twhich may cause "
 				    "on-disk corruption with 'zfs recv' and "
 				    "which needs\n\tto be corrected. Enable "
-				    "the bookmark_v2 feature, backup "
-				    "these datasets\n\tto new encrypted "
-				    "datasets, and destroy the old ones. "
-				    "If this pool does\n\tnot contain any "
-				    "encrypted datasets, simply enable the "
-				    "bookmark_v2\n\tfeature.\n"));
+				    "the bookmark_v2 feature. Destroy all "
+				    "snapshots (on encrypted datasets) that "
+				    "were created before enabling bookmark_v2. "
+				    "If preserving those snapshots is "
+				    "required, copy them to new encrypted "
+				    "datasets with zfs send. If this pool "
+				    "does\n\tnot contain any encrypted "
+				    "datasets, simply enable the bookmark_v2 "
+				    "\n\tfeature.\n"));
 				break;
 			default:
 				/*
@@ -7637,12 +7640,15 @@ status_callback(zpool_handle_t *zhp, void *data)
 			    "contain an on-disk incompatibility\n\twhich "
 			    "needs to be corrected.\n"));
 			(void) printf(gettext("action: To correct the issue "
-			    "enable the bookmark_v2 feature, backup\n\tany "
-			    "existing encrypted datasets to new encrypted "
-			    "datasets,\n\tand destroy the old ones. If this "
-			    "pool does not contain any\n\tencrypted "
+			    "enable the bookmark_v2 feature. Destroy all "
+			    "snapshots (on encrypted datasets) that "
+			    "were created before enabling bookmark_v2. "
+			    "If preserving those snapshots is "
+			    "required, copy them to new encrypted "
+			    "datasets with zfs send. If this pool "
+			    "does\n\tnot contain any encrypted "
 			    "datasets, simply enable the bookmark_v2 "
-			    "feature.\n"));
+			    "\n\tfeature.\n"));
 			break;
 
 		default: