chore(docs): add missing backtick (#169)

Author: iiio2

docs/1.guide/1.index.md

@@ -13,7 +13,7 @@ Writing a realtime WebSocket server that can work in different runtimes is chall
 > [!TIP]
 > You can try crossws with [online playground](https://stackblitz.com/github/h3js/crossws/tree/main/playground).
 
-Install `crossws` and `srvx in your project:
+Install `crossws` and `srvx` in your project:
 
 :pm-install{name="crossws srvx"}