Update index.md

Author: robfatland

index.md

@@ -50,7 +50,7 @@ The use of keywords is intended to remind one of the page's detailed focus.
         - [api](https://github.com/robfatland/nexus/blob/gh-pages/data/api.md) (keywords: NoSQL API serverless Azure periodic table ocean science data publication)
     - [hpc](https://github.com/robfatland/nexus/blob/gh-pages/hpc/index.md) (stub)
     - [cloud](https://github.com/robfatland/nexus/blob/gh-pages/cloud/index.md) (keywords: VM login using VSCode plus basics and links)
-        - [spot market / preemptibl instances](https://github.com/robfatland/nexus/blob/gh-pages/cloud/spot.md) (keywords: preemptible spot market checkpoint)
+        - [spot market / preemptible instances](https://github.com/robfatland/nexus/blob/gh-pages/cloud/spot.md) (keywords: preemptible spot market checkpoint)
         - [studies](https://github.com/robfatland/nexus/blob/gh-pages/cloud/studies.md) (keywords: SCOPED Neotoma nascent link-based stub)
         - [organizations](https://github.com/robfatland/nexus/blob/gh-pages/cloud/organizations.md) (keywords: AWS organizations services) (**Note: Rebrand as AWS-organizations**)
         - [aws object storage](https://github.com/robfatland/nexus/blob/gh-pages/cloud/aws.md) (keywords: local drive S3 object storage)