docs(samples): Adding a missing region tag

[m-strzelczyk]

Turns out I missed the compute_create_windows_instance_external_ip region tag when I first made those samples. Adding it now.

[snippet-bot]

Here is the summary of changes.

You are about to add 1 region tag.

• samples/snippets/instances/create_start_instance/create_windows_instance.py:22, tag compute_create_windows_instance_external_ip

---

This comment is generated by snippet-bot.
If you find problems with this result, please file an issue at:
https://github.com/googleapis/repo-automation-bots/issues.
To update this comment, add snippet-bot:force-run label or use the checkbox below:

• Refresh this comment

[parthea]

The 2nd region start tag is redundant and should be removed

[m-strzelczyk]

Well, I want this sample to show up in the sample browser, and those two tags are different. In other languages we have different samples for external and internal, but due to the way Python samples are created, it's pointless to create a whole new sample just to change one boolean variable, so I want this to have a START for two different regions.