Clarify that the context is IRB context (#950)

Author: st0012

lib/irb/helper_method/conf.rb

@@ -1,7 +1,7 @@
 module IRB
   module HelperMethod
     class Conf < Base
-      description "Returns the current context."
+      description "Returns the current IRB context."
 
       def execute
         IRB.CurrentContext

test/irb/command/test_help.rb

@@ -69,7 +69,7 @@ def test_help_lists_helper_methods
         type "exit"
       end
 
-      assert_match(/Helper methods\s+conf\s+Returns the current context/, out)
+      assert_match(/Helper methods\s+conf\s+Returns the current IRB context/, out)
     end
   end
 end