Add support for buffer protocol (PEP 688)

[Rogdham]

With PEP 688 being accepted and included in Python 3.12, we should accept and test for custom classes implementing the buffer protocol being passed to Parser.

Moreover, static type checkers will stop promoting bytearray/memoryview/etc. to bytes at some point, so let's anticipate that (has been tested with custom version of mypy).

Mypy patch

diff --git a/mypy/options.py b/mypy/options.py
index 5ef6bc2a3..2642b6407 100644
--- a/mypy/options.py
+++ b/mypy/options.py
@@ -375,8 +375,8 @@ class Options:
         # (undocumented feature).
         self.export_ref_info = False
 
-        self.disable_bytearray_promotion = False
-        self.disable_memoryview_promotion = False
+        self.disable_bytearray_promotion = True
+        self.disable_memoryview_promotion = True
         self.force_uppercase_builtins = False
         self.force_union_syntax = False

Errors messages in current version with patched mypy

tests/unit/test_stream.py: note: In function "test_chain_types":
tests/unit/test_stream.py:107: error: Argument 2 to "StreamChain" has incompatible type "bytearray"; expected "Streamable"  [arg-type]
tests/unit/test_stream.py:107: note: Following member(s) of "bytearray" have conflicts:
tests/unit/test_stream.py:107: note:     Expected:
tests/unit/test_stream.py:107: note:         def __iter__(self) -> Iterator[Streamable]
tests/unit/test_stream.py:107: note:     Got:
tests/unit/test_stream.py:107: note:         def __iter__(self) -> Iterator[int]
tests/unit/test_stream.py:108: error: Argument 3 to "StreamChain" has incompatible type "memoryview"; expected "Streamable"  [arg-type]
tests/unit/test_stream.py:108: note: Following member(s) of "memoryview" have conflicts:
tests/unit/test_stream.py:108: note:     Expected:
tests/unit/test_stream.py:108: note:         def __iter__(self) -> Iterator[Streamable]
tests/unit/test_stream.py:108: note:     Got:
tests/unit/test_stream.py:108: note:         def __iter__(self) -> Iterator[int]
Found 2 errors in 1 file (checked 26 source files)