Update kiwix-serve.rst

- Added region-specific adjustments: >= 5% in CN for China and >= 5% in NG for Nigeria to ensure newer versions used in these regions are included.
- Covered modern browsers to ensure compatibility with Chrome 80+, Edge 80+, Safari 14+, and Firefox 70+.
- Removed old/unmaintained browsers by using the 'not dead' rule to exclude browsers like IE11 and outdated mobile browsers.

docs/kiwix-serve.rst

@@ -19,6 +19,25 @@ search database.
 
 ``kiwix-serve`` supports Web browsers `Firefox >= 70, Chrome >= 80, Edge >= 80, ChromeAndroid >= 80, Safari >= 14, iOS >= 14 <https://browsersl.ist/#q=Firefox+%3E%3D+70%2C+Chrome+%3E%3D+80%2C+Edge+%3E%3D+80%2C+ChromeAndroid+%3E%3D+80%2C+Safari+%3E%3D+14%2C+iOS+%3E%3D+14>`_.
 
+
+The full browserslist configuration is as follows:
+```json
+"browserslist": [
+  "> 0.5%", 
+  "last 2 versions", 
+  "not dead", 
+  "supports es6-module", 
+  "Firefox >= 70", 
+  "Chrome >= 80", 
+  "Edge >= 80", 
+  "ChromeAndroid >= 80", 
+  "Safari >= 14", 
+  "iOS >= 14", 
+  ">= 5% in CN",  // China-specific adjustment
+  ">= 5% in NG"   // Nigeria-specific adjustment
+]
+
+
 Usage
 =====