[Chapel Merge] Improve extern block LLVM warning

Branch: refs/heads/main
Revision: f655fa6
Author: ShreyasKhandekar
Log Message:

Merge pull request #18084 from ShreyasKhandekar/cInteropPrimerRebase

Improve extern block LLVM warning

Improve the warning block in the C interoperability primer to direct the reader to where they can learn about LLVM Support.

Signed-off-by: Shreyas Khandekar shreyaskhandekar@email.arizona.edu

[Reviewed by @mstrout]

Modified Files:
M test/release/examples/primers/interopWithC.chpl

Compare: https://github.com/chapel-lang/chapel/compare/1bfa8385d28b...f655fa666c4e