Remove incomplete plugin behavior from README

Copilot feedback: Overview section was incomplete/misleading about plugin behavior.
Solution: Remove Overview section - complete behavior docs are in example file headers.

Author: subtleGradient

typescript/ai-sdk-v5/src/plugin-file-parser/README.md

@@ -2,14 +2,6 @@
 
 Examples demonstrating OpenRouter's FileParserPlugin with AI SDK v5.
 
-## Overview
-
-The FileParserPlugin is automatically enabled when using file attachments with the AI SDK provider. It:
-
-- Processes PDFs sent via data URIs
-- Extracts text using server-side parsing
-- Integrates seamlessly with AI SDK's message format
-
 ## Examples
 
 - `file-parser-pdf-url.ts` - Demonstrates sending PDFs via public URLs without downloading