New review comment by ahesford on void-packages repository

https://github.com/void-linux/void-packages/pull/45686#discussion_r1313464296

Comment:
```suggestion
provides="opencl-headers-${version}_${revision}"
replaces="opencl-headers>=0"
```
These lines replace an old, removed `opencl-headers` package, so they need to be carried forward from the `opencl2-headers` template verbatim.