Sort unrolled builds in rollup comment by PR number

This makes sure that they will be ordered in the same way as in the rollup PR description.

Author: Kobzol

site/src/github.rs

@@ -33,8 +33,19 @@ pub async fn unroll_rollup(
         let display = truncate.then(|| s.split_at(10).0).unwrap_or(s);
         format!("[{display}](https://github.com/rust-lang-ci/rust/commit/{s})")
     };
-    let mapping = enqueue_unrolled_try_builds(ci_client, rollup_merges, previous_master)
-        .await?
+
+    // Sort rolled up commits by their PR number in ascending order, so that they have the
+    // same ordering as in the rollup PR description.
+    let mut unrolled_builds: Vec<UnrolledCommit> =
+        enqueue_unrolled_try_builds(ci_client, rollup_merges, previous_master).await?;
+    unrolled_builds.sort_unstable_by(|a, b| {
+        a.original_pr_number
+            .parse::<u64>()
+            .and_then(|a| b.original_pr_number.parse::<u64>().map(|b| a.cmp(&b)))
+            .unwrap_or_else(|_| a.original_pr_number.cmp(b.original_pr_number))
+    });
+
+    let mapping = unrolled_builds
         .into_iter()
         .fold(String::new(), |mut string, c| {
             use std::fmt::Write;