Enhance `req.acceptsEncodings` Method `5.x`

[Abdel-Monaam-Aouini]

Enhance req.acceptsEncodings Method

This enhancement refines the req.acceptsEncodings method to improve the handling of the request's Accept-Encoding header. The updated method checks whether the client accepts the specified encoding(s) and returns the best matching encoding or an array of acceptable encodings.

Key Features:

• Supports single or multiple encoding strings and a comma-delimited list of encodings.
• Provides consistent behavior across different input formats.
• Enhances code readability and maintainability.

Examples:

• req.acceptsEncodings('gzip') returns "gzip" when the Accept-Encoding header includes "gzip".
• req.acceptsEncodings('br') returns undefined if the encoding isn't accepted by the client.
• req.acceptsEncodings('gzip, deflate') returns "gzip" as the best match.

This update ensures more robust handling of accepted encodings, improving compatibility and performance.