Fixes #97899

https://github.com/microsoft/vscode/issues/98095#issuecomment-630689079

https://github.com/microsoft/vscode/issues/97881

This reverts commit c8eccf9b.

Fixes #98135

This reverts commit a1ddfae7.

peek highlight should use reference uri, but bucket uri, https://github.com/microsoft/vscode/issues/97881

fix #98102

This reverts commit 94972252.

When VSCode selects preselected completion items, the index shouldn't start from 1. If there are multiple completion items with preselect=true, the first item will never be chosen.

This reverts commit 5d0a9392.