Error output with checkout-opticss-and-link.sh

Running `./scripts/checkout-opticss-and-link.sh` in the css-blocks root directory outputs the following error:

```bash
./scripts/checkout-opticss-and-link.sh: line 8: ./scripts/if-dev-opticss.sh: No such file or directory
./scripts/checkout-opticss-and-link.sh: line 9: ./scripts/if-dev-opticss.sh: No such file or directory
```

Run ./scripts/checkout-opticss-and-link.sh from the css-blocks root and inspect the references on lines 8-9 to ./scripts/if-dev-opticss.sh. Check the scripts directory and related checkout/link scripts to determine the intended path or missing file. Done means the command no longer reports that if-dev-opticss.sh is missing.

Written by the indexing model from the issue text.