Revert "Merge pull request #34421 from albertoalmagro/use-assert-not-instead-of-refute"

This reverts commit ab5d5c95, reversing
changes made to ef4f5ef6.

guides/bug_report_templates/generic_gem.rb

@@ -18,6 +18,6 @@
 class BugTest < Minitest::Test
   def test_stuff
     assert "zomg".present?
-    assert_not "".present?
+    refute "".present?
   end
 end

guides/bug_report_templates/generic_master.rb

@@ -17,6 +17,6 @@
 class BugTest < Minitest::Test
   def test_stuff
     assert "zomg".present?
-    assert_not "".present?
+    refute "".present?
   end
 end