Fix Style/ModuleFunction.

Library/.rubocop_todo.yml

@@ -187,8 +187,6 @@ Style/ModuleFunction:
     - 'Homebrew/os/mac.rb'
     - 'Homebrew/os/mac/xcode.rb'
     - 'Homebrew/os/mac/xquartz.rb'
-    - 'Homebrew/utils/github.rb'
-    - 'Homebrew/utils/json.rb'
 
 # Offense count: 8
 Style/MultilineBlockChain:

Library/Homebrew/utils/github.rb

@@ -2,7 +2,8 @@ require "uri"
 require "tempfile"
 
 module GitHub
-  extend self
+  module_function
+
   ISSUES_URI = URI.parse("https://api.github.com/search/issues")
 
   Error = Class.new(RuntimeError)

Library/Homebrew/utils/json.rb

@@ -2,7 +2,7 @@ require "vendor/okjson"
 
 module Utils
   module JSON
-    extend self
+    module_function
 
     Error = Class.new(StandardError)