Fix JSON schema relative links

[hoffa]

For example:

serverless-application-model/samtranslator/schema/docs.json

Line 6 in 5c82f5d

"Authorizers": "The authorizer used to control access to your API Gateway API\\. \nFor more information, see [Controlling access to API Gateway APIs](serverless-controlling-access-to-apis.md)\\. \n*Type*: [CognitoAuthorizer](sam-property-api-cognitoauthorizer.md) \\| [LambdaTokenAuthorizer](sam-property-api-lambdatokenauthorizer.md) \\| [LambdaRequestAuthorizer](sam-property-api-lambdarequestauthorizer.md) \n*Required*: No \n*Default*: None \n*AWS CloudFormation compatibility*: This property is unique to AWS SAM and doesn't have an AWS CloudFormation equivalent\\. \n*Additional notes*: SAM adds the Authorizers to the OpenApi definition of an Api\\.",

However, since the path stems match the final docs, we could replace:

[Controlling access to API Gateway APIs](serverless-controlling-access-to-apis.md)

By:

[Controlling access to API Gateway APIs](https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-controlling-access-to-apis.html)