docs: add util to generate clean markdown for a file (#11303)

www/packages/docs-utils/src/expression-is-utils.ts

@@ -0,0 +1,21 @@
+import { ExpressionJsVarLiteral, ExpressionJsVarObj } from "types"
+
+export function isExpressionJsVarLiteral(
+  expression: unknown
+): expression is ExpressionJsVarLiteral {
+  return (
+    typeof expression === "object" &&
+    expression !== null &&
+    Object.hasOwn(expression, "original")
+  )
+}
+
+export function isExpressionJsVarObj(
+  expression: unknown
+): expression is ExpressionJsVarObj {
+  return (
+    typeof expression === "object" &&
+    expression !== null &&
+    !Object.hasOwn(expression, "original")
+  )
+}