🌐 Add Chinese translation for body-multiple-params.md (#1532)

* add chinese translation for body-multiple-params.md

* improve translations

Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com>

docs/zh/mkdocs.yml

@@ -35,6 +35,7 @@ nav:
   - tutorial/query-params.md
   - tutorial/body.md
   - tutorial/query-params-str-validations.md
+  - tutorial/body-multiple-params.md
   - tutorial/path-params-numeric-validations.md
 - deployment.md
 - contributing.md