feat (docs): add generateId reference docs (#1942)

content/docs/07-reference/stream-helpers/50-generate-id.mdx

@@ -0,0 +1,38 @@
+---
+title: generateId
+description: Generate a unique identifier (API Reference)
+---
+
+# `generateId()`
+
+Generates a unique identifier. You can optionally provide the length of the ID.
+
+This is the same id generator used by the AI SDK.
+
+```ts
+import { generateId } from 'ai';
+
+const id = generateId();
+```
+
+## Import
+
+<Snippet text={`import { generateId } from "ai"`} prompt={false} />
+
+## API Signature
+
+### Parameters
+
+<PropertiesTable
+  content={[
+    {
+      name: 'size',
+      type: 'number',
+      description: `The length of the generated ID. It defaults to 8.`,
+    },
+  ]}
+/>
+
+### Returns
+
+A string representing the generated ID.

content/docs/07-reference/stream-helpers/index.mdx

@@ -110,5 +110,12 @@ description: Learn to use help functions that help stream generations from diffe
         "Transforms the response from Inkeeps's language models into a readable stream.",
       href: '/docs/reference/stream-helpers/inkeep-stream',
     },
-  ]}
+    {
+      title: 'generateId()',
+      description:
+        'Helper function for generating unique IDs',
+      href: '/docs/reference/stream-helpers/generate-id',
+    }
+
+]}
 />