[terminal] improve the display of 'new terminal'

Fixes eclipse-theia#6874

- improves the display of `new terminal` items when running in a multi-root workspace.
- adds the `root name` as a label, and displays the `uri` as a description.

Signed-off-by: Vincent Fugnitto <vincent.fugnitto@ericsson.com>

packages/terminal/src/browser/terminal-frontend-contribution.ts

@@ -368,7 +368,7 @@ export class TerminalFrontendContribution implements TerminalService, CommandCon
     protected async selectTerminalCwd(): Promise<string | undefined> {
         const roots = this.workspaceService.tryGetRoots();
         return this.quickPick.show(roots.map(
-            ({ uri }) => ({ label: this.labelProvider.getLongName(new URI(uri)), value: uri })
+            ({ uri }) => ({ label: this.labelProvider.getName(new URI(uri)), description: this.labelProvider.getLongName(new URI(uri)), value: uri })
         ), { placeholder: 'Select current working directory for new terminal' });
     }