ci: Fix comment (#824)

Author: krlmlr

.github/workflows/R-CMD-check.yaml

@@ -134,7 +134,8 @@ jobs:
 
       - id: versions-matrix
         # Only run for:
-        # - pull requests if the base repo is different from the head repo and the branch name does not start with "cran-"
+        # - pull requests if the base repo is different from the head repo
+        # - pull requests if the branch name starts with "cran-"
         # Do not run for:
         # - workflow_dispatch if not requested
         # Always run for other events.