Function fetch_srcinfo_async 

pub async fn fetch_srcinfo_async(
    client: &Client,
    name: &str,
) -> Result<String, String>

What: Fetch .SRCINFO content for an AUR package using async HTTP.

Inputs:

• client: Reqwest HTTP client.
• name: AUR package name.

Output:

• Returns .SRCINFO content as a string, or an error if fetch fails.

Errors

• Returns Err when HTTP request fails (network error or client error)
• Returns Err when HTTP response status is not successful
• Returns Err when response body cannot be read
• Returns Err when response is empty or contains HTML error page

Details:

• Uses reqwest for async fetching with built-in timeout handling.
• Validates that the response is not empty and not HTML.