Add translation of ruby-2-2-0-released (ja)
Fix ruby-2-2-0-released translation (ja)

* Consolidate the translation of "gabage"
* Use "Symbol オブジェクト" instead of "シンボル型オブジェクト"
* Fix mistranslated sentences
* etc.
Merge pull request #934 from makimoto/ruby-2-2-0-released-ja

Add translation of ruby-2-2-0-released (ja)