Is your feature request related to a problem or challenge?

In our hash util functions, we have a rehash argument across many of them:

It's not clearly obvious why we do this from the code alone; it seems it used to be named multi_col and would be true if we needed to hash multiple columns, but was changed in #6816 to also skip rehash if it is the first column, for performance reasons.

• It seems dictionary function also still calls it multi_col

I also found it confusing how certain hash functions don't have a rehash parameter; specifically the nested types such as list, struct, etc.

Describe the solution you'd like

Add some documentation explaining why we have a rehash parameter across the functions. Also look into adding rehash parameter for those hash functions missing them. If this parameter was omitted on purpose for such functions, leave an explanation of why this is the case.

Describe alternatives you've considered

No response

Additional context

No response