docs: fix error client download link

Author: wenfengwang

docs/pages/index.mdx

@@ -18,14 +18,14 @@ NPi (**N**atural-language **P**rogramming **I**nterface), pronounced as **"N π"
     <Tabs items={['macOS', 'Linux']}>
         <Tabs.Tab>
             ```sh
-            curl -O https://s.npi.ai/cli/latest/darwin/amd64/npi
+            curl -O https://s.npi.ai/cli/latest/darwin/npi
             chmod +x npi
             sudo mv npi /usr/local/bin
             ```
         </Tabs.Tab>
         <Tabs.Tab>
             ```sh
-            curl -O https://s.npi.ai/cli/latest/linux/amd64/npi
+            curl -O https://s.npi.ai/cli/latest/linux/npi
             chmod +x npi
             sudo mv npi /usr/local/bin
             ```