feat: test changes to multiple plugins at once (#753)

scripts/format.bash

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+# format Shell scripts in scripts/ directory.
+shfmt --language-dialect bash --indent 2 --write \
+  ./scripts/*
+
+# format Markdown files.
+npx -y prettier --write \
+  ./**/*.md