Solves #3433

Description

Now validate.yml workflow will also check whether the api docs are up to date with the descriptors in registry/api/v2/descriptors.go. If yes, then the job passes with no failure, If no, then the job fails will the appropriate error message.

Note: It looks like the docs/content/spec/api.md is being updated manually so there is some difference between the api markdown and the template file. I have updated the template to match the api markdown in most cases but there a few cases where it just cannot be updated:

1. Random newlines in api markdown with no specific pattern

The differences that have been addressed:

1. General spacing differences
2. "errors:" -> "errors":
3. JSON object pretty formatting
4. Text mismatch when compared to descriptor file
5. Missing block in api markdown (at the end of the file)