docs: separate install commands into individual code blocks

Author: mpsuesser

README.md

@@ -20,14 +20,18 @@ Write [oxlint](https://oxc.rs/docs/guide/usage/linter) custom lint rules with [E
 
 ## Install
 
+**npm / yarn / pnpm**
 ```sh
-# npm / yarn / pnpm
 npm install effect-oxlint effect@4.0.0-beta.43
+```
 
-# bun
+**bun**
+```sh
 bun add effect-oxlint effect@4.0.0-beta.43
+```
 
-# jsr (Deno)
+**JSR (Deno)**
+```sh
 deno add jsr:@effect-oxlint/effect-oxlint
 ```