Tweak docs

awscli/topics/config-vars.rst

@@ -201,15 +201,15 @@ in the AWS CLI config file:
 
 * ``role_arn`` - The ARN of the role you want to assume.
 * ``source_profile`` - The AWS CLI profile that contains credentials /
-  configuration we should use for the initial ``assume-role`` call. This
+  configuration the CLI should use for the initial ``assume-role`` call. This
   profile may be another profile configured to use ``assume-role``, though
-  if static credentials are present in the profile they will be preferred.
+  if static credentials are present in the profile they will take precedence.
   This parameter cannot be provided alongside ``credential_source``.
 * ``credential_source`` - The credential provider to use to get credentials for
   the initial ``assume-role`` call. This parameter cannot be provided
   alongside ``source_profile``. Valid values are:
   * ``Environment`` to pull source credentials from environment variables.
-  * ``Ec2InstanceMetadta`` to use the EC2 instance role as source credentials.
+  * ``Ec2InstanceMetadata`` to use the EC2 instance role as source credentials.
   * ``EcsContainer`` to use the ECS container credentials as the source
     credentials.
 * ``external_id`` - A unique identifier that is used by third parties to assume
@@ -255,7 +255,8 @@ Example configuration using ``source_profile``::
   role_arn=arn:aws:iam:...
   source_profile=development
 
-Example configuration using ``credential_source``::
+Example configuration using ``credential_source`` to use the instance role as
+the source credentials for the assume role call::
 
   # In ~/.aws/config
   [profile crossaccount]