Add a type annotation

Add the type annotation for Node.pretty.key_separator

CHANGELOG.md

@@ -12,6 +12,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Bumped minimum Python version to 3.7 https://github.com/Textualize/rich/pull/2567
 - Pretty-printing of "tagged" `__repr__` results is now greedy when matching tags https://github.com/Textualize/rich/pull/2565
 
+### Added
+- Add type annotation for key_separator of pretty.Node https://github.com/Textualize/rich/issues/2625
+
 ## [12.6.0] - 2022-10-02
 
 ### Added

rich/pretty.py

@@ -433,7 +433,7 @@ class Node:
     is_tuple: bool = False
     is_namedtuple: bool = False
     children: Optional[List["Node"]] = None
-    key_separator = ": "
+    key_separator: str = ": "
     separator: str = ", "
 
     def iter_tokens(self) -> Iterable[str]: