doc: Improve links in sync/async section

Author: anubhav756

README.md

@@ -183,8 +183,8 @@ result = await tool.ainvoke({"param1": "value1", "param2": "value2"})
 
 | Package                 | Loading Tools                                                                                                                                                                                                                            | Invoking Tools                                                                                                                                                                 | Docs                                                                                                              |
 | :---------------------- | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :---------------------------------------------------------------------------------------------------------------- |
-| **`toolbox-core`** | **Async:**<br/>* &nbsp;**Class:** `ToolboxClient`<br/>* &nbsp;**Methods:**<br/>&nbsp;&nbsp;&nbsp;* &nbsp;`await client.load_tool()`<br/>&nbsp;&nbsp;&nbsp;* &nbsp;`await client.load_toolset()`<br/><br/>**Sync:**<br/>* &nbsp;**Class:** `ToolboxSyncClient`<br/>* &nbsp;**Methods:**<br/>&nbsp;&nbsp;&nbsp;* &nbsp;`client.load_tool()`<br/>&nbsp;&nbsp;&nbsp;* &nbsp;`client.load_toolset()` | **Async:**<br/>* &nbsp;**Class:** `ToolboxTool`<br/>* &nbsp;**Invocation:** `await tool(...)`<br/><br/>**Sync:**<br/>* &nbsp;**Class:** `ToolboxSyncTool`<br/>* &nbsp;**Invocation:** `tool(...)`       | [`toolbox-core` README](./packages/toolbox-core/README.md)                                                     |
-| **`toolbox-langchain`** | **Unified Class:** `ToolboxClient`<br/><br/>* &nbsp;**Async Methods:**<br/>&nbsp;&nbsp;&nbsp;* &nbsp;`await client.aload_tool()`<br/>&nbsp;&nbsp;&nbsp;* &nbsp;`await client.aload_toolset()`<br/><br/>* &nbsp;**Sync Methods:**<br/>&nbsp;&nbsp;&nbsp;* &nbsp;`client.load_tool()`<br/>&nbsp;&nbsp;&nbsp;* &nbsp;`client.load_toolset()` | **Unified Class:** `ToolboxTool`<br/><br/>* &nbsp;**Async Method:** `await tool.ainvoke()`<br/><br/>* &nbsp;**Sync Method:** `tool.invoke()`                                                   | [`toolbox-langchain` README](./packages/toolbox-langchain/README.md#synchronous-and-asynchronous-usage) |
+| **`toolbox-core`** | **Async:**<br/>* &nbsp;**Class:** `ToolboxClient`<br/>* &nbsp;**Methods:**<br/>&nbsp;&nbsp;&nbsp;* &nbsp;`await client.load_tool()`<br/>&nbsp;&nbsp;&nbsp;* &nbsp;`await client.load_toolset()`<br/><br/>**Sync:**<br/>* &nbsp;**Class:** `ToolboxSyncClient`<br/>* &nbsp;**Methods:**<br/>&nbsp;&nbsp;&nbsp;* &nbsp;`client.load_tool()`<br/>&nbsp;&nbsp;&nbsp;* &nbsp;`client.load_toolset()` | **Async:**<br/>* &nbsp;**Class:** `ToolboxTool`<br/>* &nbsp;**Invocation:** `await tool(...)`<br/><br/>**Sync:**<br/>* &nbsp;**Class:** `ToolboxSyncTool`<br/>* &nbsp;**Invocation:** `tool(...)`       | [`toolbox-core` README](https://github.com/googleapis/mcp-toolbox-sdk-python/blob/main/packages/toolbox-core/README.md#synchronous-usage)                                                     |
+| **`toolbox-langchain`** | **Unified Class:** `ToolboxClient`<br/><br/>* &nbsp;**Async Methods:**<br/>&nbsp;&nbsp;&nbsp;* &nbsp;`await client.aload_tool()`<br/>&nbsp;&nbsp;&nbsp;* &nbsp;`await client.aload_toolset()`<br/><br/>* &nbsp;**Sync Methods:**<br/>&nbsp;&nbsp;&nbsp;* &nbsp;`client.load_tool()`<br/>&nbsp;&nbsp;&nbsp;* &nbsp;`client.load_toolset()` | **Unified Class:** `ToolboxTool`<br/><br/>* &nbsp;**Async Method:** `await tool.ainvoke()`<br/><br/>* &nbsp;**Sync Method:** `tool.invoke()`                                                   | [`toolbox-langchain` README](https://github.com/googleapis/mcp-toolbox-sdk-python/blob/main/packages/toolbox-langchain/README.md#asynchronous-usage) |
 
 The `ToolboxSyncClient` handles communication with the Toolbox service *synchronously* and produces `ToolboxSyncTool` instances when you load tools. You do not use the `await` keyword when interacting with these synchronous versions.