chore: enable pyupgrade fixes (#1806)

# What does this PR do?

The goal of this PR is code base modernization.

Schema reflection code needed a minor adjustment to handle UnionTypes
and collections.abc.AsyncIterator. (Both are preferred for latest Python
releases.)

Note to reviewers: almost all changes here are automatically generated
by pyupgrade. Some additional unused imports were cleaned up. The only
change worth of note can be found under `docs/openapi_generator` and
`llama_stack/strong_typing/schema.py` where reflection code was updated
to deal with "newer" types.

Signed-off-by: Ihar Hrachyshka <ihar.hrachyshka@gmail.com>

llama_stack/strong_typing/docstring.py

@@ -11,6 +11,7 @@ Type-safe data interchange for Python data classes.
 """
 
 import builtins
+import collections.abc
 import dataclasses
 import inspect
 import re
@@ -171,6 +172,13 @@ class SupportsDoc(Protocol):
     __doc__: Optional[str]
 
 
+def _maybe_unwrap_async_iterator(t):
+    origin_type = typing.get_origin(t)
+    if origin_type is collections.abc.AsyncIterator:
+        return typing.get_args(t)[0]
+    return t
+
+
 def parse_type(typ: SupportsDoc) -> Docstring:
     """
     Parse the docstring of a type into its components.
@@ -178,6 +186,8 @@ def parse_type(typ: SupportsDoc) -> Docstring:
     :param typ: The type whose documentation string to parse.
     :returns: Components of the documentation string.
     """
+    # Use docstring from the iterator origin type for streaming apis
+    typ = _maybe_unwrap_async_iterator(typ)
 
     doc = get_docstring(typ)
     if doc is None:

llama_stack/strong_typing/schema.py

@@ -10,6 +10,7 @@ Type-safe data interchange for Python data classes.
 :see: https://github.com/hunyadi/strong_typing
 """
 
+import collections.abc
 import dataclasses
 import datetime
 import decimal
@@ -487,6 +488,9 @@ class JsonSchemaGenerator:
         elif origin_type is type:
             (concrete_type,) = typing.get_args(typ)  # unpack single tuple element
             return {"const": self.type_to_schema(concrete_type, force_expand=True)}
+        elif origin_type is collections.abc.AsyncIterator:
+            (concrete_type,) = typing.get_args(typ)
+            return self.type_to_schema(concrete_type)
 
         # dictionary of class attributes
         members = dict(inspect.getmembers(typ, lambda a: not inspect.isroutine(a)))