[Docs] Fix typo

Replaced incorrect "a MCP" with "an MCP" two source code comments
to match the correct usage based on pronunciation.

Author: koic

src/server/stdio.ts

@@ -5,7 +5,7 @@ import { JSONRPCMessage } from '../types.js';
 import { Transport } from '../shared/transport.js';
 
 /**
- * Server transport for stdio: this communicates with a MCP client by reading from the current process' stdin and writing to stdout.
+ * Server transport for stdio: this communicates with an MCP client by reading from the current process' stdin and writing to stdout.
  *
  * This transport is only available in Node.js environments.
  */

src/shared/transport.ts

@@ -26,7 +26,7 @@ export type TransportSendOptions = {
     onresumptiontoken?: (token: string) => void;
 };
 /**
- * Describes the minimal contract for a MCP transport that a client or server can communicate over.
+ * Describes the minimal contract for an MCP transport that a client or server can communicate over.
  */
 export interface Transport {
     /**