contributing/void-docs: remove folder with one file.

Just use a void-docs.md file directly.

Author: ericonr

src/SUMMARY.md

@@ -76,4 +76,4 @@
       - [Common Issues](./xbps/troubleshooting/common-issues.md)
       - [Static XBPS](./xbps/troubleshooting/static.md)
 - [Contributing](./contributing/index.md)
-   - [Contributing To void-docs](./contributing/void-docs/index.md)
+   - [Contributing To void-docs](./contributing/void-docs.md)