docs(changelog): remove unnecessary entries

[cerkiner]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/angular/angular/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation content changes
• angular.io application / infrastructure changes
• Other... Please describe:

What is the current behavior?

Unnecessary, repeating entries in the changelog

Issue Number: N/A

What is the new behavior?

Remove unnecessary, repeating entries in the changelog

Does this PR introduce a breaking change?

• Yes
• No

Other information

The earliest mention of each entry is kept and duplicate entries mentioned in newer versions are removed.

[cerkiner]

Is anyone interested in this fix? @filipesilva @atscott

[cerkiner]

Is anyone interested in this fix? @kara

[kapunahelewong]

Hi @cerkiner, thank you for this PR. I'm sorry for the delay. We are working on catching up with the issues and PRs backlog. I have added the appropriate labels, including PR action: review, which puts it in the queue for engineering to review. Just so you know, ultimately you will need to rebase. If that's not part of your regular workflow, I can help you with it. If you have any questions in the meantime, just tag me.

[IgorMinar]

the second commit looks good, but the first one has removals which I don't understand.

Can you please explain what key you used to determine which entries to keep and which to remove?

Also, can you please follow our commit message convention and ensure that the CI lint checks pass? thanks

[IgorMinar]

Reviewed-for: public-api

[cerkiner]

@IgorMinar I first realised there are duplicate entries for same changes and fixes, while I am fixing the issue, I realised there are some titles with no entries.

6972401 Removes duplicate entries by keeping the earliest mention of each entry.
d24de59 Removes the empty titles

I can apply the same changes to recent change log entries as well.

[jelbourn]

@cerkiner would you mind squashing your changes into just two commits?

docs(changelog): remove duplicate entries

Remove duplicate entries in the changelog, keeping only the earliest instance of changes that appear multiple times.

docs(changelog): remove empty sections

The changelog contains some empty sections (such as `### Bug Fixes`). This change removes these empty sections.

[cerkiner]

@jelbourn Thank you for the copy, I used it exactly as is. I also applied the same changes to recent changelog entries.

[jelbourn]

LGTM

Reviewed-for: global-approvers

Commit message has been updated

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}