CloudFormation Resource Specification and Resource Provider Schemas are missing many allowed values from documentation

### Resource Name

Applies to many, a few examples are:
- AWS::CloudWatch::Alarm (`ComparisonOperator` property)
- AWS::EC2::Instance (`InstanceType`, `InstanceInitiatedShutdownBehavior`, `Tenancy` properties)

### Details

The Cloudformation Docs for `AWS::CloudWatch::Alarm` say that `ComparisonOperator` has
> Allowed values: `GreaterThanOrEqualToThreshold` | `GreaterThanThreshold` | `LessThanThreshold` | `LessThanOrEqualToThreshold` | `LessThanLowerOrGreaterThanUpperThreshold` | `LessThanLowerThreshold` | `GreaterThanUpperThreshold`

Yet the CloudFormation Resource Specification and Resource Provider Schemas for `us-west-2` lack any metadata about allowed values, just that the value type is `string`.

Where are the docs being generated from? The **Allowed values** sections seem like they're probably generated from _some_ schema that we need access to...
I generate TypeScript types for Cloudformation templates from these schemas, but they're not helping me catch typos.

Should I just scrape the docs pages?

Compare the AWS::CloudWatch::Alarm and AWS::EC2::Instance documentation with the us-west-2 CloudFormation Resource Specification and Resource Provider Schemas, focusing on the named properties and their allowed values. Trace where the documentation metadata is generated from; done means the source of those values and the required schema or documentation change are identified.

Written by the indexing model from the issue text.