fix: typo in toolkit install guide with dnf (NVIDIA#356)

Signed-off-by: Christopher Desiniotis <cdesiniotis@nvidia.com>

Author: cdesiniotis

container-toolkit/install-guide.md

@@ -101,7 +101,7 @@ where `systemd` cgroup drivers are used that cause containers to lose access to
    Optionally, configure the repository to use experimental packages:
 
    ```console
-   $ sudo dnf-config-manager --enable nvidia-container-toolkit-experimental
+   $ sudo dnf config-manager --enable nvidia-container-toolkit-experimental
    ```
 
 1. Install the NVIDIA Container Toolkit packages:
@@ -246,4 +246,4 @@ For Podman, NVIDIA recommends using [CDI](./cdi-support.md) for accessing NVIDIA
 
 ## Next Steps
 
-- [](./sample-workload.md)
+- [](./sample-workload.md)