Improve code block formatting in README.md (#1381)

Updated code block formatting for clarity in README to enable proper
syntax highlighting on vercel.com/templates

### Description

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welcome!
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### Demo URL

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### Type of Change

- [ ] New Example
- [ ] Example updates (Bug fixes, new features, etc.)
- [ ] Other (changes to the codebase, but not to examples)

### New Example Checklist

- [ ] 🛫 `npm run new-example` was used to create the example
- [ ] 📚 The template wasn't used but I carefuly read the [Adding a new
example](https://github.com/vercel/examples#adding-a-new-example) steps
and implemented them in the example
- [ ] 📱 Is it responsive? Are mobile and tablets considered?

Author: christopherkindl

framework-boilerplates/hono-bun/README.md

@@ -8,25 +8,25 @@ Prerequisites:
 
 To develop locally:
 
-```
+```bash
 bun install
 vc dev
 ```
 
-```
+```bash
 open http://localhost:3000
 ```
 
 To build locally:
 
-```
+```bash
 bun install
 vc build
 ```
 
 To deploy:
 
-```
+```bash
 bun install
 vc deploy
 ```