Update changelogs from fern repo (#6928)

Co-authored-by: thesandlord <8902396+thesandlord@users.noreply.github.com>

Author: thesandlord

fern/products/cli-api-reference/cli-changelog/2026-09-11.mdx

@@ -1,3 +1,9 @@
+## 5.120.5
+**`(fix):`** Fix `theme.tabs.placement` / `theme.tabs.alignment` being sent to the docs publishing API in lowercase,
+which caused `fern generate --docs` to fail with `config.theme.tabs: Invalid input` even though
+`fern check` passed.
+
+
 ## 5.120.4
 **`(fix):`** Honor `required` on OpenAPI response headers: header value types are only wrapped in
 `optional` when the Header Object does not declare `required: true`, matching the