Add PowerShell snippet for setting TARGET_API_URL environment variable (#36800)

Author: rufer7

data/reusables/enterprise-migration-tool/set-target-api-url.md

@@ -1,7 +1,15 @@
-1. If you're migrating to {% data variables.enterprise.data_residency %}, for convenience, set an environment variable for the **base API URL** for your enterprise. For example:
+1. If you're migrating to {% data variables.enterprise.data_residency %}, for convenience, set an environment variable for the **base API URL** for your enterprise.
 
-   ```shell copy
-   export TARGET_API_URL="https://api.{% data variables.enterprise.data_residency_example_domain %}"
-   ```
+   * If you're using Terminal, use the `export` command.
+
+     ```shell copy
+     export TARGET_API_URL="https://api.{% data variables.enterprise.data_residency_example_domain %}"
+     ```
+
+   * If you're using PowerShell, use the `$env` command.
+
+     ```shell copy
+     $env:TARGET_API_URL="https://api.{% data variables.enterprise.data_residency_example_domain %}"
+     ```
 
    You'll use this variable with the `--target-api-url` option in commands you run with the {% data variables.product.prodname_cli %}.