Update changelogs from fern repo (#5288)

Co-authored-by: dsinghvi <10870189+dsinghvi@users.noreply.github.com>

Author: fern-support

fern/products/sdks/generators/python/changelog/2026-05-01.mdx

@@ -0,0 +1,16 @@
+## 5.9.1
+**`(fix):`** Respect the customer's `smart-casing` flag from `generators.yml` when computing
+Python identifiers from compressed v66 IR strings. Previously the v1 Python
+generator's `_smart_snake` and v2's `PYTHON_CASE_CONVERTER` were both hardcoded
+with `smartCasing: true`, causing names produced by the generator to diverge
+from the IR's pre-computed `snake_case` values when the customer set
+`smart-casing: false`. This manifested as wire-test method calls and Pydantic
+field aliases that did not exist on the generated client (e.g. test calling
+`set_fcmv_1_provider()` while the client method was named `set_fcmv1provider`).
+
+`_smart_snake` and the v2 `caseConverter` now read `casingsConfig.smartCasing`
+from the IR and switch between smart-casing semantics (default) and plain
+lodash semantics (`smart-casing: false`). No effect for customers who use
+the default; fixes generation for customers like auth0 that opt out.
+
+