rel_eng/upload: Clarify usage directions

Previously it was not made clear that the directory name is significant.

.gitlab/rel_eng/upload.sh

@@ -6,9 +6,9 @@ set -Eeuo pipefail
 # This is a script for preparing and uploading a release of GHC.
 #
 # Usage,
-#   1. Update $ver
-#   2. Set $SIGNING_KEY to your key id (prefixed with '=')
-#   3. Create a directory and place the source and binary tarballs there
+#   1. Set $SIGNING_KEY to your key id (prefixed with '=')
+#   2. Create a directory named after the release name (e.g. 9.6.1-rc1 or 9.6.1)
+#   3. Place the source and binary tarballs in this directory
 #   4. Run this script from that directory
 #
 # You can also invoke the script with an argument to perform only
@@ -34,10 +34,10 @@ set -Eeuo pipefail
 : ${SIGNING_KEY:="=Benjamin Gamari <ben@well-typed.com>"}
 
 
-# Infer release name from directory name
+# Infer friendly release name from directory name
 : ${rel_name:=$(basename $(pwd))}
 
-# Infer version from tarball names
+# Infer project version from tarball names
 : ${ver:=$(ls ghc-*.tar.* | sed -ne 's/ghc-\([0-9]\+\.[0-9]\+\.[0-9]\+\(\.[0-9]\+\)\?\).\+/\1/p' | head -n1)}
 if [ -z "$ver" ]; then echo "Failed to infer \$ver"; exit 1; fi