Fix typo in installation.md (#6731)

### Description

bellow -> below

### Types of changes
<!--- Put an `x` in all the boxes that apply, and remove the not
applicable items -->
- [x] Non-breaking change (fix or new feature that would not break
existing functionality).
- [ ] Breaking change (fix or new feature that would cause existing
functionality to change).
- [ ] New tests added to cover the changes.
- [ ] Integration tests passed locally by running `./runtests.sh -f -u
--net --coverage`.
- [ ] Quick tests passed locally by running `./runtests.sh --quick
--unittests --disttests`.
- [ ] In-line docstrings updated.
- [ ] Documentation updated, tested `make html` command in the `docs/`
folder.

Signed-off-by: Ikko Eltociear Ashimine <[email protected]>

docs/source/installation.md

@@ -30,7 +30,7 @@ Ignite](https://pytorch.org/ignite/), please follow the instructions:
 
 - [Installing the recommended dependencies](#installing-the-recommended-dependencies)
 
-The installation commands bellow usually end up installing CPU variant of PyTorch. To install GPU-enabled PyTorch:
+The installation commands below usually end up installing CPU variant of PyTorch. To install GPU-enabled PyTorch:
 
 1. Install the latest NVIDIA driver.
 1. Check [PyTorch Official Guide](https://pytorch.org/get-started/locally/) for the recommended CUDA versions. For Pip package, the user needs to download the CUDA manually, install it on the system, and ensure CUDA_PATH is set properly.