arrow

GH-43509: [R]  Add link to ?acero from ?list_compute_functions (#44210)

### Rationale for this change

Add link between docs pages to make it easier to find relevant information

### What changes are included in this PR?

Update docs 

### Are these changes tested?

Nope

### Are there any user-facing changes?

Sure, to the docs
* GitHub Issue: #43509

Authored-by: Nic Crane <thisisnic@gmail.com>
Signed-off-by: Bryce Mecum <petridish@gmail.com>