docs: make it easy to add more other translations (#5874)

Co-authored-by: YobeZhou <smilezyb@163.com>

docs/add_translation.py

@@ -1,6 +1,25 @@
 #!/usr/bin/env python3
 import os
 
+"""
+Please add the translation language you want to add here, while also modifying the variable URL_BASE in _ext/link_roles.py
+For example:
+
+LANGUAGE =  ':link_to_translation:`zh_CN:[中文]`\t'  + \
+            ':link_to_translation:`en:[English]`\t' + \
+            '\n\n'
+
+
+URL_BASE = {
+    "zh_CN": "https://lvgl.100ask.net/",
+    "en": "https://docs.lvgl.io/"
+}
+"""
+
+LANGUAGE =  ':link_to_translation:`zh_CN:[中文]`\t'  + \
+            '\n\n'
+
+
 
 def find_files(dir_path, suffix):
     files = []
@@ -20,4 +39,4 @@ def exec(temp_directory):
         with open(rst_file, 'r+', encoding='utf-8') as f:
             content = f.read()
             f.seek(0, 0)
-            f.write(':link_to_translation:`zh_CN:[中文]`\n\n' + content)
+            f.write(LANGUAGE + content)