feat: Document invoking tools with hyphens

Documents the bugfix implemented in strands-agents/sdk-python#178 where underscores take the place of hyphens

Author: zastrowm

docs/user-guide/concepts/tools/tools_overview.md

@@ -76,6 +76,13 @@ Every tool added to an agent also becomes a method accessible directly on the ag
 result = agent.tool.file_read(path="/path/to/file.txt", mode="view")
 ```
 
+If a tool name contains hyphens, you can invoke the tool using underscores instead:
+
+```python
+# Directly invoke a tool named "read-all"
+result = agent.tool.read_all(path="/path/to/file.txt")
+```
+
 ## Building & Loading Tools
 
 ### 1. Python Tools