[Feature] Enable persist_docs to automatically inherit descriptions from upstream columns (like dbt Cloud Explorer can)

[jeremyyeo]

Is this your first time submitting a feature request?

• I have read the expectations for open source contributors
• I have searched the existing issues, and I could not find an existing issue for this feature
• I am requesting a straightforward extension of existing dbt functionality, rather than a Big Idea better suited to a discussion

Describe the feature

Filing this on behalf of a customer - they would like the native dbt-core persist_docs functionality to be able to propagate upstream column descriptions to downstream ones as well without having to copy the descriptions multiple times. For example:

-- models/foo.sql
select 1 id

-- models/bar.sql
select * from {{ ref('foo') }}

# dbt_project.yml
...
models:
  +persist_docs: 
    columns: true

# models/schema.yml
models:
  - name: foo
    columns:
      - name: id
        description: The id.

^ Right now, this means that only foo.id will have a description be applied to it - but it would be useful if dbt also automatically added col descriptions for bar.id as well.

dbt Cloud Explorer currently is able to propagate column descriptions with it's CLL.

Describe alternatives you've considered

No response

Who will this benefit?

No response

Are you interested in contributing this feature?

No response

Anything else?

No response