[.NET] Use collection expressions

As of C# 12 we can now use collection expressions to reduce some boilerplate when initializing collections.

tutorials/networking/http_client_class.rst

@@ -139,7 +139,11 @@ It will connect and fetch a website.
             Debug.Assert(http.GetStatus() == HTTPClient.Status.Connected); // Check if the connection was made successfully.
 
             // Some headers.
-            string[] headers = { "User-Agent: Pirulo/1.0 (Godot)", "Accept: */*" };
+            string[] headers =
+            [
+                "User-Agent: Pirulo/1.0 (Godot)",
+                "Accept: */*",
+            ];
 
             err = http.Request(HTTPClient.Method.Get, "/ChangeLog-5.php", headers); // Request a page from the site.
             Debug.Assert(err == Error.Ok); // Make sure all is OK.

tutorials/networking/http_request_class.rst

@@ -127,7 +127,7 @@ But what if you need to send data to the server? Here is a common way of doing i
     .. code-tab:: csharp
 
         string json = Json.Stringify(dataToSend);
-        string[] headers = new string[] { "Content-Type: application/json" };
+        string[] headers = ["Content-Type: application/json"];
         HttpRequest httpRequest = GetNode<HttpRequest>("HTTPRequest");
         httpRequest.Request(url, headers, HttpClient.Method.Post, json);
 
@@ -147,7 +147,7 @@ For example, to set a custom user agent (the HTTP ``User-Agent`` header) you cou
     .. code-tab:: csharp
 
         HttpRequest httpRequest = GetNode<HttpRequest>("HTTPRequest");
-        httpRequest.Request("https://api.github.com/repos/godotengine/godot/releases/latest", new string[] { "User-Agent: YourCustomUserAgent" });
+        httpRequest.Request("https://api.github.com/repos/godotengine/godot/releases/latest", ["User-Agent: YourCustomUserAgent"]);
 
 .. danger::