site: update the nixpkgs package link

This link is no longer valid because of Nixpkgs package refactoring.

Closes #11263.

PiperOrigin-RevId: 309244512
diff --git a/site/docs/install.md b/site/docs/install.md
index 6c11627..e8f1172 100644
--- a/site/docs/install.md
+++ b/site/docs/install.md
@@ -18,7 +18,7 @@
 *   [FreeBSD](https://www.freshports.org/devel/bazel)
 *   [Gentoo](https://packages.gentoo.org/packages/dev-util/bazel)
 *   [Linuxbrew](https://github.com/Linuxbrew/homebrew-core/blob/master/Formula/bazel.rb)
-*   [Nixpkgs](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/tools/build-managers/bazel/default.nix)
+*   [Nixpkgs](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/tools/build-managers/bazel)
 *   [openSUSE](install-suse.md)
 *   [Parabola](https://www.parabola.nu/packages/?q=bazel)
 *   [Scoop](https://github.com/scoopinstaller/scoop-main/blob/master/bucket/bazel.json)