Merge pull request rails#27166 from mtsmfm/rename-minitest

[ci skip] `MiniTest` -> `Minitest`

Author: kaspth

railties/test/code_statistics_calculator_test.rb

@@ -24,7 +24,7 @@ def foo
     end
   end
 
-  test "count number of methods in MiniTest file" do
+  test "count number of methods in Minitest file" do
     code = <<-RUBY
       class FooTest < ActionController::TestCase
         test 'expectation' do