R Editor Support is not compatible with visual studio code version 1.95.3
Indeed, it would be good to update the minimal Code version (or be less restrictive in the dependency: https://github.com/REditorSupport/vscode-R-syntax/issues/9) as since the reditorsupport.r-syntax was added as a dependency, >1.75 is no longer true
https://github.com/REditorSupport/vscode-R/blob/61088253ee8adf32933590cd436e2bb93c6f3597/package.json#L28-L30
https://github.com/REditorSupport/vscode-R/blob/61088253ee8adf32933590cd436e2bb93c6f3597/package.json#L2040-L2042
This serious requirement change was/is unfortunately not documented: https://github.com/REditorSupport/vscode-R/releases/tag/v2.8.6 | https://github.com/REditorSupport/vscode-R/blob/master/CHANGELOG.md
FYI, in order to use this extension on Code OSS <1.96.2, the latest working version is 2.8.5. From the Visual Studio martketplace, directly from the UI in VSCode, you can install an older version. For Positron or other IDE not supporting Visual Studio martketplace but using Open VSX:
- Go to https://open-vsx.org/extension/REditorSupport/r/2.8.5
- Download the VSIX file via the "download" button
- Install manually (refer to the documentation of your IDE if you don't know how)