Merge pull request #5152 from...

Merge pull request #5152 from shuujii/move-lib-mruby-core-ext.rb-to-lib-mruby-core_ext.rb-for-consistency

Move `lib/mruby-core-ext.rb` to `lib/mruby/core_ext.rb` for consistency

Rakefile

@@ -10,7 +10,7 @@ Rake.verbose(false) if Rake.verbose == Rake::DSL::DEFAULT
 $LOAD_PATH << File.join(MRUBY_ROOT, "lib")
 
 # load build systems
-require "mruby-core-ext"
+require "mruby/core_ext"
 require "mruby/build"
 
 # load configuration file

lib/mruby/build.rb

-require "mruby-core-ext"
+require "mruby/core_ext"
 require "mruby/build/load_gems"
 require "mruby/build/command"