v0.5.12

What's Changed

• Add comment for RuleAction by @yui-knk in #278
• Organize rbs in grammar and lexer/token by @ydah in #279
• Update LEGAL.md to add new file under template/bison/ by @yui-knk in #280
• NEWS.md by @yui-knk in #281
• Install NEWS.md into ruby by @yui-knk in #282
• Remove TODO.md by @yui-knk in #283
• v0.5.12 by @yui-knk in #284

Full Changelog: v0.5.11...v0.5.12