In some cases we'll get an `ImmutableListProtocol[str]` anyway (and
actually, we should probably be getting one in call cases), since we
don't mutate it anyway, just store it as immutable.
This finds uses of deny-listed functions, which defaults to map and
filter. These functions should be replaced by comprehensions in
idiomatic python because:
1. comprehensions are more heavily optimized and are often faster
2. They avoid the need for lambdas in some cases, which make them
faster
3. you can do the equivalent in one statement rather than two, which
is faster
4. They're easier to read
5. if you need a concrete instance (ie, a list) then you don't have
to convert the iterator to a list afterwards
Thanks to `ModuleInfo`, all modules are just named `foo.py` instead of
`unstable_foo.py`, which simplifies the import method a bit. This also
allows for accurate FeatureNew/FeatureDeprecated use, as we know when
the module was added and if/when it was stabilized.
Eli Schwartz