Expose zh-cn docs, delete bad zh docs, add docs for adding translations (#6855)

* expose zh-cn docs, delete bad zh docs, add docs for adding translations

* Update docs/translating.md

Co-Authored-By: noroadsleft <18669334+noroadsleft@users.noreply.github.com>

* Update docs/translating.md

Co-Authored-By: noroadsleft <18669334+noroadsleft@users.noreply.github.com>

* update for python 3

docs/_summary.md

@@ -109,6 +109,7 @@
   * [Using Eclipse with QMK](other_eclipse.md)
   * [Using VSCode with QMK](other_vscode.md)
   * [Support](support.md)
+  * [How to add translations](translating.md)
 
 * QMK Internals (In Progress)
   * [Defines](internals_defines.md)