chore: Maintain consistency in the doc (#3832)

Maintain consistency in the doc like here: 


https://github.com/Alamofire/Alamofire/blob/5c68811d8b1eb4ac312a3968fa54e88a31a33abc/Source/Features/AuthenticationInterceptor.swift#L27

Signed-off-by: hugo-syn <hugo.vincent@synacktiv.com>

Source/Core/Request.swift

@@ -192,7 +192,7 @@ public class Request {
 
     // MARK: URLRequests
 
-    /// All `URLRequests` created on behalf of the `Request`, including original and adapted requests.
+    /// All `URLRequest`s created on behalf of the `Request`, including original and adapted requests.
     public var requests: [URLRequest] { mutableState.requests }
     /// First `URLRequest` created on behalf of the `Request`. May not be the first one actually executed.
     public var firstRequest: URLRequest? { requests.first }

Source/Core/URLConvertible+URLRequestConvertible.swift

@@ -25,7 +25,7 @@
 import Foundation
 
 /// Types adopting the `URLConvertible` protocol can be used to construct `URL`s, which can then be used to construct
-/// `URLRequests`.
+/// `URLRequest`s.
 public protocol URLConvertible {
     /// Returns a `URL` from the conforming instance or throws.
     ///