chore(internal): detect missing future annotations with ruff

Author: stainless-app[bot]

pyproject.toml

@@ -256,6 +256,8 @@ select = [
   "B",
   # remove unused imports
   "F401",
+  # check for missing future annotations
+  "FA102",
   # bare except statements
   "E722",
   # unused arguments
@@ -278,6 +280,8 @@ unfixable = [
   "T203",
 ]
 
+extend-safe-fixes = ["FA102"]
+
 [tool.ruff.lint.flake8-tidy-imports.banned-api]
 "functools.lru_cache".msg = "This function does not retain type information for the wrapped function's arguments; The `lru_cache` function from `_utils` should be used instead"