add nomicon translate for zh-CN

Author: PureWhiteWu

locales/zh-CN/learn.ftl

@@ -42,6 +42,8 @@ learn-reference-button = 阅读《参考手册》
 learn-nomicon-alt = 双手捧火
 learn-nomicon = 《Rust 秘典》是 Unsafe Rust 的黑魔法指南。它有时被称作“死灵书”。
 learn-nomicon-button = 阅读《Rust 秘典》
+translated-nomicon = https://nomicon.purewhite.io/
+translated-nomicon-button = 阅读非官方翻译
 learn-unstable-alt = 手洒星光
 learn-unstable = 《未稳定特性手册》覆盖了当前只能在 nightly Rust 中使用的还未稳定的特性。
 learn-unstable-button = 阅读《未稳定特性手册》

templates/learn/index.hbs

@@ -177,6 +177,7 @@
              href="https://doc.rust-lang.org/nomicon/index.html">
             {{fluent "learn-nomicon-button"}}
           </a>
+          {{#if (fluent "translated-nomicon")}}<a class="button-additional" href={{fluent "translated-nomicon"}}>{{fluent "translated-nomicon-button"}}</a>{{/if}}
         </div>
       </div>