starlark docs: do not claim lambdas unsupported
Fixes
RELNOTES: None.
@@ -144,7 +144,6 @@ The following Python features are not supported:
* `while`, `yield`.
* float and set types.
* generators and generator expressions.
-* `lambda` and nested functions.
* `is` (use `==` instead).
* `try`, `raise`, `except`, `finally` (see [`fail`](lib/globals.html#fail) for fatal errors).
* `global`, `nonlocal`.
