build: use different base path for dev and prod

Author: idiotWu

docs/next.config.js

@@ -1,9 +1,11 @@
+const isProd = process.env.NODE_ENV === 'production';
+
 const withNextra = require('nextra')({
   theme: 'nextra-theme-docs',
   themeConfig: './theme.config.tsx',
   defaultShowCopyCode: true,
 });
 
 module.exports = withNextra({
-  basePath: '/docs'
+  basePath: isProd ? '/docs' : '',
 });