Routes manifest is not updated without dev server restart

### What is the problem?

Routes manifest is not updated without a dev server restart

### Paste all your error logs here:

None

### Paste all relevant code snippets here:

None

### What are detailed steps to reproduce this?

1. `blitz dev`
2. Add a new page named `export default TestPage`
3. Add link to that new page using the Routes manifest, `Routes.TestPage()`
4. See error in the browser that `TestPage` is not a function

### Run `blitz -v` and paste the output here:

```
macOS Monterey | darwin-arm64 | Node: v16.13.0

blitz: 0.42.4 (global)
blitz: 0.43.0 (local)

Package manager: npm
System:
OS: macOS 12.0.1
CPU: (10) arm64 Apple M1 Max
Memory: 66.69 MB / 64.00 GB
Shell: 3.3.1 - /opt/homebrew/bin/fish
Binaries:
Node: 16.13.0 - /var/folders/gf/xyzbs8n52kz_sxxvpw2psh1r0000gn/T/fnm_multishells/33678_1637356936901/bin/node
Yarn: 1.22.17 - /opt/homebrew/bin/yarn
npm: 8.1.0 - /opt/homebrew/bin/npm
Watchman: 2021.11.08.00 - /opt/homebrew/bin/watchman
npmPackages:
@prisma/client: 2.30.0 => 2.30.0
blitz: 0.43.0 => 0.43.0
prisma: 2.30.0 => 2.30.0
react: 18.0.0-alpha-b9964684b-20210824 => 18.0.0-alpha-b9964684b-20210824
react-dom: 18.0.0-alpha-b9964684b-20210824 => 18.0.0-alpha-b9964684b-20210824
typescript: Not Found
```

### Please include below any other applicable logs and screenshots that show your problem:

_No response_