chore: fix ruff linting and mypy issues in knowledge module

src/crewai/knowledge/source/json_knowledge_source.py

@@ -1,6 +1,6 @@
 import json
 from pathlib import Path
-from typing import Any, Dict, List
+from typing import Any
 
 from crewai.knowledge.source.base_file_knowledge_source import BaseFileKnowledgeSource
 
@@ -8,9 +8,9 @@ from crewai.knowledge.source.base_file_knowledge_source import BaseFileKnowledge
 class JSONKnowledgeSource(BaseFileKnowledgeSource):
     """A knowledge source that stores and queries JSON file content using embeddings."""
 
-    def load_content(self) -> Dict[Path, str]:
+    def load_content(self) -> dict[Path, str]:
         """Load and preprocess JSON file content."""
-        content: Dict[Path, str] = {}
+        content: dict[Path, str] = {}
         for path in self.safe_file_paths:
             path = self.convert_to_path(path)
             with open(path, "r", encoding="utf-8") as json_file:
@@ -29,7 +29,7 @@ class JSONKnowledgeSource(BaseFileKnowledgeSource):
             for item in data:
                 text += f"{indent}- {self._json_to_text(item, level + 1)}\n"
         else:
-            text += f"{str(data)}"
+            text += f"{data!s}"
         return text
 
     def add(self) -> None:
@@ -44,7 +44,7 @@ class JSONKnowledgeSource(BaseFileKnowledgeSource):
         self.chunks.extend(new_chunks)
         self._save_documents()
 
-    def _chunk_text(self, text: str) -> List[str]:
+    def _chunk_text(self, text: str) -> list[str]:
         """Utility method to split text into chunks."""
         return [
             text[i : i + self.chunk_size]