Regenerate the README files and fix the Open in Cloud Shell link for some samples [(googleapis#1441)](GoogleCloudPlatform/python-docs-samples#1441)

Author: chenyumic

samples/samples/README.rst

@@ -12,7 +12,7 @@ This directory contains samples for Google Cloud Spanner. `Google Cloud Spanner`
 
 
 
-.. _Google Cloud Spanner: https://cloud.google.com/spanner/docs 
+.. _Google Cloud Spanner: https://cloud.google.com/spanner/docs
 
 Setup
 -------------------------------------------------------------------------------
@@ -59,7 +59,7 @@ Snippets
 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 
 .. image:: https://gstatic.com/cloudssh/images/open-btn.png
-   :target: https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/GoogleCloudPlatform/python-docs-samples&page=editor&open_in_editor=spanner/cloud-client/snippets.py;spanner/cloud-client/README.rst
+   :target: https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/GoogleCloudPlatform/python-docs-samples&page=editor&open_in_editor=spanner/cloud-client/snippets.py,spanner/cloud-client/README.rst
 
 
 
@@ -72,7 +72,7 @@ To run this sample:
 
     usage: snippets.py [-h] [--database-id DATABASE_ID]
                        instance_id
-                       {create_database,insert_data,query_data,read_data,read_stale_data,add_column,update_data,query_data_with_new_column,read_write_transaction,read_only_transaction,add_index,query_data_with_index,read_data_with_index,add_storing_index,read_data_with_storing_index}
+                       {create_database,insert_data,query_data,read_data,read_stale_data,add_column,update_data,query_data_with_new_column,read_write_transaction,read_only_transaction,add_index,query_data_with_index,read_data_with_index,add_storing_index,read_data_with_storing_index,create_table_with_timestamp,insert_data_with_timestamp,add_timestamp_column,update_data_with_timestamp,query_data_with_timestamp}
                        ...
 
     This application demonstrates how to do basic operations using Cloud
@@ -82,7 +82,7 @@ To run this sample:
 
     positional arguments:
       instance_id           Your Cloud Spanner instance ID.
-      {create_database,insert_data,query_data,read_data,read_stale_data,add_column,update_data,query_data_with_new_column,read_write_transaction,read_only_transaction,add_index,query_data_with_index,read_data_with_index,add_storing_index,read_data_with_storing_index}
+      {create_database,insert_data,query_data,read_data,read_stale_data,add_column,update_data,query_data_with_new_column,read_write_transaction,read_only_transaction,add_index,query_data_with_index,read_data_with_index,add_storing_index,read_data_with_storing_index,create_table_with_timestamp,insert_data_with_timestamp,add_timestamp_column,update_data_with_timestamp,query_data_with_timestamp}
         create_database     Creates a database and tables for sample data.
         insert_data         Inserts sample data into the given database. The
                             database and table must already exist and can be
@@ -139,6 +139,34 @@ To run this sample:
                             Inserts sample data into the given database. The
                             database and table must already exist and can be
                             created using `create_database`.
+        create_table_with_timestamp
+                            Creates a table with a COMMIT_TIMESTAMP column.
+        insert_data_with_timestamp
+                            Inserts data with a COMMIT_TIMESTAMP field into a
+                            table.
+        add_timestamp_column
+                            Adds a new TIMESTAMP column to the Albums table in the
+                            example database.
+        update_data_with_timestamp
+                            Updates Performances tables in the database with the
+                            COMMIT_TIMESTAMP column. This updates the
+                            `MarketingBudget` column which must be created before
+                            running this sample. You can add the column by running
+                            the `add_column` sample or by running this DDL
+                            statement against your database: ALTER TABLE Albums
+                            ADD COLUMN MarketingBudget INT64 In addition this
+                            update expects the LastUpdateTime column added by
+                            applying this DDL statement against your database:
+                            ALTER TABLE Albums ADD COLUMN LastUpdateTime TIMESTAMP
+                            OPTIONS(allow_commit_timestamp=true)
+        query_data_with_timestamp
+                            Queries sample data from the database using SQL. This
+                            updates the `LastUpdateTime` column which must be
+                            created before running this sample. You can add the
+                            column by running the `add_timestamp_column` sample or
+                            by running this DDL statement against your database:
+                            ALTER TABLE Performances ADD COLUMN LastUpdateTime
+                            TIMESTAMP OPTIONS (allow_commit_timestamp=true)
 
     optional arguments:
       -h, --help            show this help message and exit