Issue 1698 add examples for az repos import create command (#1321)

* Issue 1698 add examples for az repos import create command

Fixes Azure/azure-cli-extensions#1698

* Update _help.py

azure-devops/azext_devops/dev/repos/_help.py

@@ -40,7 +40,12 @@ def load_repos_help():
     helps['repos import'] = """
     type: group
     short-summary: Manage Git repositories import
-    long-summary:
+    long-summary: This command imports the public repo fabrikam-open-source to the empty Git repo fabrikam-open-source for the default configuration
+                  az devops configure --defaults organization=https://dev.azure.com/fabrikamprime project="Fabrikam Fiber".
+    examples:
+          - name: Manage Git repositories import.
+            text: |
+                az repos import create --git-source-url https://github.com/fabrikamprime/fabrikam-open-source --repository fabrikam-open-source
     """
 
     helps['repos policy'] = """