fix: Add nixpacks configuration for Astro deployment

dealplustech-astro/node_modules/mdast-util-to-markdown/lib/util/format-heading-as-setext.js

@@ -0,0 +1,34 @@
+/**
+ * @import {State} from 'mdast-util-to-markdown'
+ * @import {Heading} from 'mdast'
+ */
+
+import {EXIT, visit} from 'unist-util-visit'
+import {toString} from 'mdast-util-to-string'
+
+/**
+ * @param {Heading} node
+ * @param {State} state
+ * @returns {boolean}
+ */
+export function formatHeadingAsSetext(node, state) {
+  let literalWithBreak = false
+
+  // Look for literals with a line break.
+  // Note that this also
+  visit(node, function (node) {
+    if (
+      ('value' in node && /\r?\n|\r/.test(node.value)) ||
+      node.type === 'break'
+    ) {
+      literalWithBreak = true
+      return EXIT
+    }
+  })
+
+  return Boolean(
+    (!node.depth || node.depth < 3) &&
+      toString(node) &&
+      (state.options.setext || literalWithBreak)
+  )
+}