Update changelogs from fern repo (#920)

Co-authored-by: patrickthornton <[email protected]>

Author: fern-support

fern/products/cli-api-reference/cli-changelog/2025-09-22.mdx

@@ -1,3 +1,7 @@
+## 0.78.5
+**`(fix):`** Correct `nullable<>` wrapping of nullable schemas referenced via `$ref`.
+
+
 ## 0.78.4
 **`(fix):`** Collapse any combination of optional and nullable to optional<nullable<T>>.