Add a separate explicit message for architectures which are not supported for an image

This is to handle explicitly the case of images that were supported once but are no longer supported (like "openjdk" on s390x and ppc64le).

.template-helpers/generate-dockerfile-links-partial.sh

@@ -13,6 +13,11 @@ if [ -z "${BASHBREW_LIBRARY:-}" ]; then
 	repo="https://github.com/docker-library/official-images/raw/master/library/$repo"
 fi
 
+if [ -n "$ARCH_SPECIFIC_DOCS" ] && archTags="$(bashbrew cat --format '{{ range .Entries }}{{ if .HasArchitecture arch }}{{ .Tags | first }}{{ "\n" }}{{ end }}{{ end }}' "$repo")" && [ -z "$archTags" ]; then
+	echo "**WARNING:** THIS IMAGE *IS NOT SUPPORTED* ON THE \`$BASHBREW_ARCH\` ARCHITECTURE"
+	exit
+fi
+
 bashbrew cat \
-		-F "$(dirname "$BASH_SOURCE")/$(basename "$BASH_SOURCE" .sh).tmpl" \
-		"$repo"
+	-F "$(dirname "$BASH_SOURCE")/$(basename "$BASH_SOURCE" .sh).tmpl" \
+	"$repo"