2024.3 Build Support

[Unthrottled]

Description

• Updated Kotlin to 2.0.0 because that's what the platform is going to have
• Updated some of the APIs to match the 2024.3 SDK
• Removed the janky markdown to HTML plugin (probably putting it back later with the changelog plugin?)

Starting with version 2024.3, there will be a dedicated JSON plugin, replacing the JSON module that was previously part of the platform. Therefore, please declare an explicit dependency on com.intellij.modules.json to ensure compatibility with version 2024.3. In the meantime, we have limited the until-build to 242.* for the plugin Doki Theme.

☝️ Message from the plugin peoples, so going to have to re-instate that, but the 2024.3 build doesn't work on my machine, something about the instance not being registered well.

Motivation and Context

Closes #803

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project (./gradlew check passes clean).
  • Tip: If you have lint issues just run ./gradlew :ktlintMainSourceSetFormat.
• I updated the version.
• I updated the changelog with the new functionality.