fix migration doc formatting

mpeddada1 · mpeddada1 · commit 883c1d55f15a · 2025-12-20T02:34:37.000Z
diff --git a/doc/v3-migration-guide.md b/doc/v3-migration-guide.md
@@ -218,6 +218,8 @@ auto client = bigtable::MakeInstanceAdminClient(
 ```
 
 </details>
+
+
 ### Pubsub
 
 ### Spanner
