Fix broken anchor link in mcp.mdx (#551)

Author: Paul-Cornell

examplecode/tools/mcp.mdx

@@ -81,7 +81,7 @@ You are now ready to start coding.
 
 <Tip>
     If you are not interested in building an MCP server from the beginning and want to use a pre-built MCP server instead, 
-    skip ahead to [Optional Step 4: Extend the MCP server](#optional-step-4-extend-the-mcp-server).
+    skip ahead to [Optional Step 4: Extend the MCP server](#optional-step-4%3A-extend-the-mcp-server).
 </Tip>
 
 <Steps>
@@ -494,4 +494,4 @@ To use Unstructured's initial experimental MCP server implementation, do the fol
         - `List all available workflows.`
         - `Delete the worklow with ID <workflow-id>.`
     </Step>
-</Steps>
+</Steps>