Link is outdated

[austin362667]

Describe the bug

In documentation how-to-add-a-new-scalar-function, "here for array functions" is outdated.

Screen.Recording.2024-08-13.at.7.29.11.PM.mov

To Reproduce

https://github.com/apache/datafusion/tree/main/datafusion/functions-array

Expected behavior

https://github.com/apache/datafusion/tree/main/datafusion/functions-nested

Additional context

No response