Remove incorrect str possibility from HostnameResolver.getaddrinfo (#2964)

`_socket.getaddrinfo` takes care of encoding all passed in `str` host
arguments before passing it to a custom resolver. Additionally, the
docs say that a resolver will always receive IDNA-encoded bytes.

However, the type hints of `HostnameResolver.getaddrinfo` imply that a
resolver may need to contend with a `str`

Remove the extraneous appearance

Author: tjstum

src/trio/_abc.py

@@ -168,7 +168,7 @@ class HostnameResolver(metaclass=ABCMeta):
     @abstractmethod
     async def getaddrinfo(
         self,
-        host: bytes | str | None,
+        host: bytes | None,
         port: bytes | str | int | None,
         family: int = 0,
         type: int = 0,

src/trio/_tests/test_highlevel_open_tcp_listeners.py

@@ -231,7 +231,7 @@ class FakeHostnameResolver(HostnameResolver):
 
     async def getaddrinfo(
         self,
-        host: bytes | str | None,
+        host: bytes | None,
         port: bytes | str | int | None,
         family: int = 0,
         type: int = 0,

src/trio/_tests/test_highlevel_open_tcp_stream.py

@@ -294,7 +294,7 @@ def _ip_to_gai_entry(self, ip: str) -> tuple[
 
     async def getaddrinfo(
         self,
-        host: str | bytes | None,
+        host: bytes | None,
         port: bytes | str | int | None,
         family: int = -1,
         type: int = -1,

src/trio/_tests/test_highlevel_ssl_helpers.py

@@ -49,7 +49,7 @@ class FakeHostnameResolver(trio.abc.HostnameResolver):
 
     async def getaddrinfo(
         self,
-        host: bytes | str | None,
+        host: bytes | None,
         port: bytes | str | int | None,
         family: int = 0,
         type: int = 0,

src/trio/testing/_fake_net.py

@@ -138,7 +138,7 @@ class FakeHostnameResolver(trio.abc.HostnameResolver):
 
     async def getaddrinfo(
         self,
-        host: bytes | str | None,
+        host: bytes | None,
         port: bytes | str | int | None,
         family: int = 0,
         type: int = 0,