chore(samples): add sample for spanner editions (#3304)

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- [ ] Make sure to open an issue as a [bug/issue](https://togithub.com/googleapis/java-spanner/issues/new/choose) before writing your code!  That way we can discuss the change, evaluate designs, and agree on the general idea
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- [ ] Appropriate docs were updated (if necessary)

Fixes #<issue_number_goes_here> ☕️

If you write sample code, please follow the [samples format](
https://togithub.com/GoogleCloudPlatform/java-docs-samples/blob/main/SAMPLE_FORMAT.md).

samples/snippets/src/main/java/com/example/spanner/CreateInstanceExample.java

@@ -16,7 +16,7 @@
 
 package com.example.spanner;
 
-//[START spanner_create_instance]
+// [START spanner_create_instance]
 
 import com.google.cloud.spanner.Spanner;
 import com.google.cloud.spanner.SpannerOptions;
@@ -45,25 +45,25 @@ static void createInstance(String projectId, String instanceId) {
     Instance instance =
         Instance.newBuilder()
             .setDisplayName(displayName)
+            .setEdition(Instance.Edition.STANDARD)
             .setNodeCount(nodeCount)
-            .setConfig(
-                InstanceConfigName.of(projectId, "regional-us-east4").toString())
+            .setConfig(InstanceConfigName.of(projectId, "regional-us-east4").toString())
             .build();
 
     try (Spanner spanner =
-        SpannerOptions.newBuilder()
-            .setProjectId(projectId)
-            .build()
-            .getService();
+            SpannerOptions.newBuilder().setProjectId(projectId).build().getService();
         InstanceAdminClient instanceAdminClient = spanner.createInstanceAdminClient()) {
 
       // Wait for the createInstance operation to finish.
-      Instance createdInstance = instanceAdminClient.createInstanceAsync(
-          CreateInstanceRequest.newBuilder()
-              .setParent(ProjectName.of(projectId).toString())
-              .setInstanceId(instanceId)
-              .setInstance(instance)
-              .build()).get();
+      Instance createdInstance =
+          instanceAdminClient
+              .createInstanceAsync(
+                  CreateInstanceRequest.newBuilder()
+                      .setParent(ProjectName.of(projectId).toString())
+                      .setInstanceId(instanceId)
+                      .setInstance(instance)
+                      .build())
+              .get();
       System.out.printf("Instance %s was successfully created%n", createdInstance.getName());
     } catch (ExecutionException e) {
       System.out.printf(
@@ -74,4 +74,4 @@ static void createInstance(String projectId, String instanceId) {
     }
   }
 }
-//[END spanner_create_instance]
+// [END spanner_create_instance]

samples/snippets/src/main/java/com/example/spanner/UpdateInstanceExample.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.spanner;
+
+// [START spanner_update_instance]
+
+import com.google.cloud.spanner.Spanner;
+import com.google.cloud.spanner.SpannerOptions;
+import com.google.cloud.spanner.admin.instance.v1.InstanceAdminClient;
+import com.google.common.collect.Lists;
+import com.google.protobuf.FieldMask;
+import com.google.spanner.admin.instance.v1.Instance;
+import com.google.spanner.admin.instance.v1.InstanceConfigName;
+import com.google.spanner.admin.instance.v1.InstanceName;
+import com.google.spanner.admin.instance.v1.UpdateInstanceRequest;
+import java.util.concurrent.ExecutionException;
+
+public class UpdateInstanceExample {
+
+  static void updateInstance() {
+    // TODO(developer): Replace these variables before running the sample.
+    String projectId = "my-project";
+    String instanceId = "my-instance";
+    updateInstance(projectId, instanceId);
+  }
+
+  static void updateInstance(String projectId, String instanceId) {
+    // Set Instance configuration.
+    int nodeCount = 2;
+    String displayName = "Updated name";
+
+    // Update an Instance object that will be used to update the instance.
+    Instance instance =
+        Instance.newBuilder()
+            .setName(InstanceName.of(projectId, instanceId).toString())
+            .setDisplayName(displayName)
+            .setNodeCount(nodeCount)
+            .setEdition(Instance.Edition.ENTERPRISE)
+            .setConfig(InstanceConfigName.of(projectId, "regional-us-east4").toString())
+            .build();
+
+    try (Spanner spanner =
+            SpannerOptions.newBuilder().setProjectId(projectId).build().getService();
+        InstanceAdminClient instanceAdminClient = spanner.createInstanceAdminClient()) {
+
+      // Wait for the updatedInstance operation to finish.
+      Instance updatedInstance =
+          instanceAdminClient
+              .updateInstanceAsync(
+                  UpdateInstanceRequest.newBuilder()
+                      .setFieldMask(
+                          FieldMask.newBuilder().addAllPaths(Lists.newArrayList("edition")))
+                      .setInstance(instance)
+                      .build())
+              .get();
+      System.out.printf("Instance %s was successfully updated%n", updatedInstance.getName());
+    } catch (ExecutionException e) {
+      System.out.printf(
+          "Error: Updating instance %s failed with error message %s%n",
+          instance.getName(), e.getMessage());
+    } catch (InterruptedException e) {
+      System.out.println("Error: Waiting for updateInstance operation to finish was interrupted");
+    }
+  }
+}
+
+// [END spanner_update_instance]