Turn a #map into #each where the return value is unused

The return value of RubyProject.add_to_load_path is neither useful nor
used anywhere. In this case, #each communicates intent better than #map.

Author: leocassarani

lib/rspec/core/ruby_project.rb

@@ -6,7 +6,7 @@ module Core
     # @private
     module RubyProject
       def add_to_load_path(*dirs)
-        dirs.map { |dir| add_dir_to_load_path(File.join(root, dir)) }
+        dirs.each { |dir| add_dir_to_load_path(File.join(root, dir)) }
       end
 
       def add_dir_to_load_path(dir)