[llvm] [llvm][release] Add links to automatically built packages (PR #147719)

[David Spickett via llvm-commits]

================
@@ -45,9 +45,26 @@ def create_release(repo, release, tag=None, name=None, message=None):
         # Note that these lines are not length limited because if we do so, GitHub
         # assumes that should be how it is laid out on the page. We want GitHub to
         # do the reflowing for us instead.
+        #
+        # Once all the atuomatic binary builds have completed, the HTML comments
+        # in the text below will be removed to reveal the download links.
         message = dedent(
             """\
-LLVM {release} Release
+## LLVM {release} Release
+
+<!-- DOWNLOAD_LINKS_BEGIN
+**Linux:**
+* [x86_64](https://github.com/llvm/llvm-project/releases/download/llvmorg-{release}/LLVM-{release}-Linux-X64.tar.xz) ([signature](https://github.com/llvm/llvm-project/releases/download/llvmorg-{release}/LLVM-{release}-Linux-X64.tar.xz.jsonl))
+* [Arm64](https://github.com/llvm/llvm-project/releases/download/llvmorg-{release}/LLVM-{release}-Linux-ARM64.tar.xz) ([signature](https://github.com/llvm/llvm-project/releases/download/llvmorg-{release}/LLVM-{release}-Linux-ARM64.tar.xz.jsonl))
+
+**macOS:**
+* [Apple Silicon](https://github.com/llvm/llvm-project/releases/download/llvmorg-{release}/LLVM-{release}-macOS-ARM64.tar.xz) (ARM64) ([signature](https://github.com/llvm/llvm-project/releases/download/llvmorg-{release}/LLVM-{release}-macOS-ARM64.tar.xz.jsonl))
+* [Intel](https://github.com/llvm/llvm-project/releases/download/llvmorg-{release}/LLVM-{release}-macOS-X64.tar.xz) (x86-64) ([signature](https://github.com/llvm/llvm-project/releases/download/llvmorg-{release}/LLVM-{release}-macOS-X64.tar.xz.jsonl))
+DOWNLOAD_LINKS_END -->
+
+Download links for Linux and macOS will appear here when all the builds have completed. <!-- DOWNLOAD_LINKS_PLACEHOLDER -->
+
+For Windows, and any other variants of platform and architecture, check the full list of release packages at the bottom of this release page.
----------------
DavidSpickett wrote:

In the comment below is the final content after all comments get removed. So this would be once automatic builds are done and all the release uploaders have done their bits. I've checked that it renders the same here in a comment as on the release page.

https://github.com/llvm/llvm-project/pull/147719