Document -nvidia variants in public SSM parameters

Explain the naming convention for NVIDIA variants as part of the
documentation for our public SSM parameters.

QUICKSTART-ECS.md

@@ -40,6 +40,9 @@ Supported variants and architectures are described in the [README](README.md#var
 For the purposes of SSM parameters, the valid architecture names are `x86_64` and `arm64` (also known as `aarch64`).
 Also, if you know a specific Bottlerocket version you'd like to use, for example `1.0.6`, you can replace `latest` with that version.
 
+Bottlerocket ECS variants with NVIDIA support append `-nvidia` to the variant name.
+For instance, the NVIDIA variant corresponding to `aws-ecs-2` is `aws-ecs-2-nvidia`.
+
 Once you have the parameter name you want to use, the easiest way to use it is to pass it directly to EC2.
 Just prefix the parameter name with `resolve:ssm:` and EC2 will fetch the current value for you.
 (You can also use this method for CloudFormation and other services that launch EC2 instances for you.)

QUICKSTART-EKS.md

@@ -105,6 +105,9 @@ Supported variants and architectures are described in the [README](README.md#var
 For the purposes of SSM parameters, the valid architecture names are `x86_64` and `arm64` (also known as `aarch64`).
 Also, if you know a specific Bottlerocket version you'd like to use, for example `1.11.0`, you can replace `latest` with that version.
 
+Bottlerocket EKS variants with NVIDIA support append `-nvidia` to the variant name.
+For instance, the variant for Kubernetes version 1.28 with NVIDIA support is `aws-k8s-1.28-nvidia`.
+
 Once you have the parameter name you want to use, the easiest way to use it is to pass it directly to EC2.
 (You can also use this method for CloudFormation and other services that launch EC2 instances for you.)
 Just prefix the parameter name with `resolve:ssm:` and EC2 will fetch the current value for you.