AWS::EC2::TransitGateway*

## 1. Title

All resources and properties matching `AWS::EC2::TransitGateway*`.

## 2. Scope of request

All properties are marked to require replacement in CloudFormation, however many properties can be updated via the API without replacement. Most notably the "Tags" property.

Example `AWS::EC2::TransitGateway-Tags` say "Update requires: Replacement", however via the AWS Console you can update tags without replacement.

Most properties I think can be updated manually (API / Console) but none of them are able to be updated via CloudFormation.

## 3. Expected behavior

CloudFormation has accurate support for the update-ability of TransitGateway-related resource proprties. "Tags" and other applicable properties should be able to be updated without the re-creation of a new resource.

## 4. Suggest specific test cases

N/A

## 5. Helpful Links to speed up research and evaluation

N/A

## 6. Category (required) - Will help with tagging and be easier to find by other users to +1

Networking & Content (VPC, Route53, API GW,...)

## 7. Any additional context (optional)

N/A

Start by reviewing the AWS::EC2::TransitGateway* resources and properties, especially the Tags property, against the corresponding AWS API and Console update behavior. Identify which properties can be updated without replacement and verify that CloudFormation's update requirements match those capabilities. Done means the applicable Transit Gateway properties accurately report their replacement behavior.

Written by the indexing model from the issue text.