Notes API: Add Type field
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### Release notes
<!-- What is the problem and solution you're proposing? This content sets the overall vision for the feature and serves as the release notes that will populate in various places, including the [release post blog](https://about.gitlab.com/releases/categories/releases/) and [Gitlab project releases](https://gitlab.com/gitlab-org/gitlab/-/releases). " -->
It is hard to differentiate between from the point of the view of the API.
### Problem to solve
When using the Notes API it hard to differentiate between different times of events e.g. if a pull request is changed because there is a new commit or when it is no longer WIP.
### Intended users
* [Sasha (Software Developer)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#sasha-software-developer)
* [Rachel (Release Manager)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#rachel-release-manager)
* [Alex (Security Operations Engineer)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#alex-security-operations-engineer)
* [Simone (Software Engineer in Test)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#simone-software-engineer-in-test)
* [Allison (Application Ops)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#allison-application-ops)
### User experience goal
Users that use Applications that use the Gitlab Notes API would have an easier time using Gitlab.
### Proposal
<!-- How are we going to solve the problem? Try to include the user journey! https://about.gitlab.com/handbook/journeys/#user-journey -->
Add a type field to the note object and add different types of notes per type of notes e.g. pull-request or issue.
### Further details
<!-- Include use cases, benefits, goals, or any other details that will help us understand the problem better. -->
A tool that listens to any event could see if it worth to issue a notification to a user or trigger another event e.g. a CI event.
### Permissions and Security
They don't require additional permissions, everything is already there just no as
good to use.
### Documentation
Document changes in the [Note API](https://docs.gitlab.com/ee/api/notes.html)
### Availability & Testing
Add test for the extended API.
### Links / references
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See the discussion here about the caveats in the Gitlab Notes API while parsing events:
https://github.com/magit/forge/issues/318
issue