fix: use KeysT for blpop and brpop keys parameter type annotation (#3987)

Fixes #3986

`blpop` and `brpop` accept a single key (str/bytes) or an iterable of
keys, which is handled internally by `list_or_args`. However, both
methods were annotated with the bare `List` type which made static
type-checkers (e.g. Pylance, mypy) reject single-string arguments.

The `KeysT = Union[KeyT, Iterable[KeyT]]` alias already exists in
`redis.typing` and is imported in this module. Updating both method
signatures to use `KeysT` aligns the annotations with the actual
runtime behaviour and eliminates the false-positive type errors.

Made-with: Cursor

Co-authored-by: Turan Almammadov <16321061+turanalmammadov@users.noreply.github.com>
Co-authored-by: petyaslavova <petya.slavova@redis.com>

Author: turanalmammadov

redis/commands/core.py

@@ -2900,7 +2900,7 @@ class ListCommands(CommandsProtocol):
     """
 
     def blpop(
-        self, keys: List, timeout: Optional[Number] = 0
+        self, keys: KeysT, timeout: Optional[Number] = 0
     ) -> Union[Awaitable[list], list]:
         """
         LPOP a value off of the first non-empty list
@@ -2921,7 +2921,7 @@ def blpop(
         return self.execute_command("BLPOP", *keys)
 
     def brpop(
-        self, keys: List, timeout: Optional[Number] = 0
+        self, keys: KeysT, timeout: Optional[Number] = 0
     ) -> Union[Awaitable[list], list]:
         """
         RPOP a value off of the first non-empty list