fix(repository): amend annotations on reflog identity

Since set_ident() already has type annotations, it
seems fitting that we adorn ident() with those too. :)

Also, to_bytes() is perfectly capable of mapping None
to ffi.NULL, so the parameters on set_ident() should be
`str | None` (aka Optional[str]).

Signed-off-by: Ethan Meng <ethan@rapidcow.org>

Author: rapidcow

pygit2/repository.py

@@ -1578,7 +1578,7 @@ def get_attr(
     # Identity for reference operations
     #
     @property
-    def ident(self):
+    def ident(self) -> tuple[Optional[str], Optional[str]]:
         cname = ffi.new('char **')
         cemail = ffi.new('char **')
 
@@ -1587,7 +1587,7 @@ def ident(self):
 
         return (maybe_string(cname[0]), maybe_string(cemail[0]))
 
-    def set_ident(self, name: str, email: str) -> None:
+    def set_ident(self, name: Optional[str], email: Optional[str]) -> None:
         """Set the identity to be used for reference operations.
 
         Updates to some references also append data to their