Refine publishing message (#2624)

diff --git a/lib/src/command/lish.dart b/lib/src/command/lish.dart
index d2a710b..b42fa0b 100644
--- a/lib/src/command/lish.dart
+++ b/lib/src/command/lish.dart
@@ -187,7 +187,8 @@
       return warnings.isEmpty;
     }
 
-    log.message('\nUploads to pub.dev are subject to https://pub.dev/policy');
+    log.message('\nPublishing is forever; packages cannot be unpublished.'
+        '\nPolicy details are available at https://pub.dev/policy');
 
     final package = entrypoint.root;
     var message = 'Do you want to publish ${package.name} ${package.version}';