Add support for color of the auto import area

[movahhedi]

VSCode treats the imports above files (especially JS/TS) files as a special area (It adds a collapse button next to the first import). I'd like my import areas to have a color so I know how much to scroll at a glance.

Adding region comments for the import area of every file isn't quite elegant.

Keep in mind:

• As long as the statements are top-level, imports can occur every where in a file, even at the end (although I say it's bad practice), but that import area ends just before the first line of non-import code.
• Imports can have comments between them.

May be useful:

• https://github.com/microsoft/vscode-docs/blob/9f69164ec2c1d8c9009e092c4637dfb1f06310ae/release-notes/v1_59.md#automatically-fold-imports