chore: Minor documentation refactoring on the new changelog process.

[marcosuma]

Description

Please include a summary of the fix/feature/change, including any relevant motivation and context.

Link to any related issue(s): https://jira.mongodb.org/browse/CLOUDP-243940

Type of change:

• Bug fix (non-breaking change which fixes an issue). Please, add the "bug" label to the PR.
• New feature (non-breaking change which adds functionality). Please, add the "enhancement" label to the PR. A migration guide must be created or updated if the new feature will go in a major version.
• Breaking change (fix or feature that would cause existing functionality to not work as expected). Please, add the "breaking change" label to the PR. A migration guide must be created or updated.
• This change requires a documentation update
• Documentation fix/enhancement

Required Checklist:

• I have signed the MongoDB CLA
• I have read the contributing guides
• I have checked that this change does not generate any credentials and that they are NOT accidentally logged anywhere.
• I have added tests that prove my fix is effective or that my feature works per HashiCorp requirements
• I have added any necessary documentation (if appropriate)
• I have run make fmt and formatted my code
• If changes include deprecations or removals, I defined an isolated PR with a relevant title as it will be used in the auto-generated changelog.
• If changes include removal or addition of 3rd party GitHub actions, I updated our internal document. Reach out to the APIx Integration slack channel to get access to the internal document.

Further comments

[marcosuma]

Ref: https://github.com/mongodb/terraform-provider-mongodbatlas/actions/runs/8720632791/job/23922580319?pr=2162

Now error is printed like this:

2024/04/17 10:53:21 Changelog file .changelog/2162.txt not found due to the following reason: open .changelog/2162.txt: no such file or directory.
Have you ran the `make generate-changelog-entry` command?
If this PR doesn't need a changelog entry file, consider using label skip-changelog-check.
Read contributing guides (https://github.com/mongodb/terraform-provider-mongodbatlas/blob/master/contributing/changelog-process.md) for more info.
exit status 1

[lantoli]

I personally prefer to have the error detail (errFile) at the end of the message. It's normally additional info that you may not need, and I think we can get a clearer message.

[AgustinBettati]

LGTM