增加俄语翻译

Author: helloyongyang

_includes/header.html

@@ -23,6 +23,7 @@
             <button class="translate-option"        data-lang="ja"   data-label="日本語">🇯🇵 日本語</button>
             <button class="translate-option"        data-lang="ko"   data-label="KO">🇰🇷 한국어</button>
             <button class="translate-option"        data-lang="de"   data-label="DE">🇩🇪 Deutsch</button>
+            <button class="translate-option"        data-lang="ru"   data-label="RU">🇷🇺 Русский</button>
             <button class="translate-option"        data-lang="es"   data-label="ES">🇪🇸 Español</button>
             <button class="translate-option"        data-lang="pt"   data-label="PT">🇧🇷 Português</button>
             <button class="translate-option"        data-lang="ar"   data-label="AR">🇸🇦 العربية</button>