fixes #27566

fixes #27525

fixes #27532

* return `undefined` when current word or selection is falsy
* use editor selection, not snippet selection, when resolving variables

For #24961

Picks up https://github.com/Microsoft/TypeScript/pull/16084/files

Allows users to manually set the npm install location

Fix some issues with dnd to the terminal

This reverts commit 85a56e64.

- \, quote chars and space are now escaped.
- Paths from the file system are now properly passed through URI, causing \ to
  be pasted in correctly.

Fixes #27511