Update README.md (microsoft#18963)

Fixed a small spelling error.

### Description
<!-- Describe your changes. -->
Small spelling error fix.


### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
It is documentation for the product, and it misspells the word
documentation. This reflects on your product and the quality of the
work.

README.md

@@ -10,7 +10,7 @@
 
 * **General Information**: [onnxruntime.ai](https://onnxruntime.ai)
 
-* **Usage documention and tutorials**: [onnxruntime.ai/docs](https://onnxruntime.ai/docs)
+* **Usage documentation and tutorials**: [onnxruntime.ai/docs](https://onnxruntime.ai/docs)
 
 * **YouTube video tutorials**: [youtube.com/@ONNXRuntime](https://www.youtube.com/@ONNXRuntime)