Wrote release notes and put them in a place more visible in VS Code (#740)

* Wrote release notes and put them in a place more visible in VS Code

* Also provide the bugs metadata

* Small tweaks

* Fix a few typos

* Split up section on DSL features

* Update rascal-vscode-extension/CHANGELOG.md

Co-authored-by: sungshik <16154899+sungshik@users.noreply.github.com>

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Co-authored-by: Rodin Aarssen <rodin.aarssen@swat.engineering>
Co-authored-by: Sung-Shik Jongmans <sung-shik.jongmans@swat.engineering>
Co-authored-by: sungshik <16154899+sungshik@users.noreply.github.com>

Author: 3 people