fix(docs): correct BetaAsyncAbstractMemoryTool docstring for async usage

The docstring example for BetaAsyncAbstractMemoryTool was copy-pasted from
the synchronous BetaAbstractMemoryTool class without being updated for async
usage, causing TypeError when following the example verbatim.

Changes:
- Use BetaAsyncAbstractMemoryTool as base class (was BetaAbstractMemoryTool)
- Use async def for method definitions (was sync def)
- Use AsyncAnthropic client (was Anthropic)
- Add await to the run_tools call

Fixes #1290

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: abdelhadi703

src/anthropic/lib/tools/_beta_builtin_memory_tool.py

@@ -157,30 +157,31 @@ def clear_all_memory(self) -> BetaFunctionToolResultType:
 
 
 class BetaAsyncAbstractMemoryTool(BetaAsyncBuiltinFunctionTool):
-    """Abstract base class for memory tool implementations.
+    """Abstract base class for async memory tool implementations.
 
-    This class provides the interface for implementing a custom memory backend for Claude.
+    This class provides the interface for implementing a custom memory backend for Claude
+    with async/await support.
 
     Subclass this to create your own memory storage solution (e.g., database, cloud storage, encrypted files, etc.).
 
     Example usage:
 
     ```py
-    class MyMemoryTool(BetaAbstractMemoryTool):
-        def view(self, command: BetaMemoryTool20250818ViewCommand) -> BetaFunctionToolResultType:
+    class MyMemoryTool(BetaAsyncAbstractMemoryTool):
+        async def view(self, command: BetaMemoryTool20250818ViewCommand) -> BetaFunctionToolResultType:
             ...
             return "view result"
 
-        def create(self, command: BetaMemoryTool20250818CreateCommand) -> BetaFunctionToolResultType:
+        async def create(self, command: BetaMemoryTool20250818CreateCommand) -> BetaFunctionToolResultType:
             ...
             return "created successfully"
 
         # ... implement other abstract methods
 
 
-    client = Anthropic()
+    client = AsyncAnthropic()
     memory_tool = MyMemoryTool()
-    message = client.beta.messages.run_tools(
+    message = await client.beta.messages.run_tools(
         model="claude-sonnet-4-5",
         messages=[{"role": "user", "content": "Remember that I like coffee"}],
         tools=[memory_tool],