Added links to SigV4 for reference

Author: vllyakho

SageMaker/connection-sigv4/README.md

@@ -1,6 +1,6 @@
 ## Connecting to Amazon Keyspaces from SageMaker Notebook with Python
 
-This code shows how to connect to Amazon Keyspaces from SageMaker using an authentication plugin for temporary credentials. This plugin enables IAM users, roles, and federated identities to add authentication information to Amazon Keyspaces API requests using the AWS Signature Version 4 process (SigV4).
+This code shows how to connect to Amazon Keyspaces from SageMaker using an authentication plugin for temporary credentials. This plugin enables IAM users, roles, and federated identities to add authentication information to Amazon Keyspaces API requests using the [AWS Signature Version 4 process (SigV4)](https://docs.aws.amazon.com/general/latest/gr/signature-version-4.html) 
 
 In this example, we do NOT need to generate Keyspaces service-specific credentials.
 
@@ -14,7 +14,7 @@ The Notebook execution role must include permissions to access Amazon Keyspaces
 See more at
 [AWS Identity and Access Management for Amazon Keyspaces](https://docs.aws.amazon.com/keyspaces/latest/devguide/security-iam.html).
 
-* To assume the role you need to have [sts:AssumeRole action](https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRole.html) permissions
+* To assume the role, you need to have [sts:AssumeRole action](https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRole.html) permissions.
     ```
     {
       "Version": "2012-10-17",  
@@ -31,7 +31,7 @@ See more at
     ```
 
 #### Note:
-Amazon Keyspaces is available in the following [AWS Regions](https://docs.aws.amazon.com/keyspaces/latest/devguide/programmatic.endpoints.html)
+Amazon Keyspaces is available in the following [AWS Regions](https://docs.aws.amazon.com/keyspaces/latest/devguide/programmatic.endpoints.html).
 
 This notebook was tested with conda_python3 kernel and should work with Python 3.x.