message: fix: elan installation on Unix
  `||` and `&&` have the same precedence in bash
diff: @@ -494,7 +494,7 @@ export class LeanInstaller implements Disposable {
  }
  else{
  const elanArgs = `-y --default-toolchain ${this.defaultToolchain}`;
  - const prompt = 'echo && read -n 1 -s -r -p "Install failed, press ENTER to continue..."';
  + const prompt = '(echo && read -n 1 -s -r -p "Install failed, press ENTER to continue...")';
  terminal.sendText(`bash -c 'curl ${this.leanInstallerLinux} -sSf | sh -s -- ${elanArgs} || ${prompt}' && exit `);
  }
  