Enable `nakayoshi_fork` by default

changelogs/unreleased/nakayoshi-default-enabled.yml

+---
+title: Enable `nakayoshi_fork` by default
+merge_request: 54688
+author:
+type: other

config/puma.example.development.rb

@@ -86,7 +86,7 @@ end
 
 # https://github.com/puma/puma/blob/master/5.0-Upgrade.md#nakayoshi_fork
 if defined?(nakayoshi_fork)
-  nakayoshi_fork if ENV['ENABLE_PUMA_NAKAYOSHI_FORK'] == 'true'
+  nakayoshi_fork unless ENV['DISABLE_PUMA_NAKAYOSHI_FORK'] == 'true'
 end
 
 # Use json formatter

config/puma.rb.example

@@ -76,7 +76,7 @@ end
 
 # https://github.com/puma/puma/blob/master/5.0-Upgrade.md#nakayoshi_fork
 if defined?(nakayoshi_fork)
-  nakayoshi_fork if ENV['ENABLE_PUMA_NAKAYOSHI_FORK'] == 'true'
+  nakayoshi_fork unless ENV['DISABLE_PUMA_NAKAYOSHI_FORK'] == 'true'
 end
 
 # Use json formatter

config/puma_actioncable.example.development.rb

@@ -86,7 +86,7 @@ end
 
 # https://github.com/puma/puma/blob/master/5.0-Upgrade.md#nakayoshi_fork
 if defined?(nakayoshi_fork)
-  nakayoshi_fork if ENV['ENABLE_PUMA_NAKAYOSHI_FORK'] == 'true'
+  nakayoshi_fork unless ENV['DISABLE_PUMA_NAKAYOSHI_FORK'] == 'true'
 end
 
 # Use json formatter