docs: update memory examples to use agent.tool.X syntax (#22)

Author: cagataycali

src/strands_tools/memory.py

@@ -42,23 +42,23 @@
 agent = Agent(tools=[memory])
 
 # Store content in Knowledge Base
-agent.memory(
+agent.tool.memory(
     action="store",
     content="Important information to remember",
     title="Meeting Notes",
     STRANDS_KNOWLEDGE_BASE_ID="my1234kb"
 )
 
 # Retrieve content using semantic search
-agent.memory(
+agent.tool.memory(
     action="retrieve",
     query="meeting information",
     min_score=0.7,
     STRANDS_KNOWLEDGE_BASE_ID="my1234kb"
 )
 
 # List all documents
-agent.memory(
+agent.tool.memory(
     action="list",
     max_results=50,
     STRANDS_KNOWLEDGE_BASE_ID="my1234kb"