Update error text for EE-specific lines check

scripts/ee-specific-lines-check

@@ -33,10 +33,11 @@ else
   puts
 
   offenses.each do |(file, delta)|
-    puts "* 💥 #{file} has #{delta - current_numstat[file]} more different lines than before! 💥"
+    puts "* 💥 #{file} has #{delta - current_numstat[file]} updated lines that differ between EE and CE! 💥"
   end
 
   say <<~MESSAGE
+    ℹ️ Make sure all lines in shared files have been updated in your backport merge request and the branch name includes #{minimal_ce_branch_name}.
     ℹ️ Consider using an EE module to add the features you want.
     ℹ️ See this for detail: https://docs.gitlab.com/ee/development/ee_features.html#ee-features-based-on-ce-features
   MESSAGE