Update .env.example for better clarity

- Revised comments for consistency and improved guidance.
- Simplified descriptions for optional variables.
- Added note to avoid committing the `.env` file.

Author: datalogics-kam

CPlusPlus/.env.example

@@ -1,16 +1,11 @@
-# Copy to ".env" and set your values.
+# pdfRest configuration for C++ samples
+# Copy to .env and set your values. Do not commit .env.
 
-# Required: pdfRest API key
+# Required: API key from https://pdfrest.com/getstarted/
 PDFREST_API_KEY=your_api_key_here
 
-# Optional: API base URL
-# - Default (US): https://api.pdfrest.com
-# - EU/GDPR region: https://eu-api.pdfrest.com
-PDFREST_URL=https://api.pdfrest.com
-# For more information visit https://pdfrest.com/pricing#how-do-eu-gdpr-api-calls-work
+# Optional: region override for EU/GDPR routing
+# PDFREST_URL=https://eu-api.pdfrest.com
 
-# Optional: Immediate deletion of sensitive files
-# - Default behavior: files are retained per the File Retention Period.
-# - Set to true to immediately delete uploaded/generated files in samples that support it.
-#   Valid values: true|false (case-insensitive)
-PDFREST_DELETE_SENSITIVE_FILES=false
+# Optional: immediate deletion of uploaded/generated files when supported
+# PDFREST_DELETE_SENSITIVE_FILES=true