.gitignore respected in a multi root workspace.

[stevenh]

When a .gitignore is defined in a standard workspace VS code explorer automatically hides all matching files, however in a multi root workspace this only works for the root workspace and others it doesn't.

The only workaround currently is to manually replicate rules form .gitignore into "settings": { "files.exclude": [] } in the workspace file, which is fragile as everyone needs to remember to update both files when making changes.

Ideally having all workspaces apply the setting would be the default but any option to have this enabled would be great.