Readability: Rename isSent() method to areHeadersSent

That way, the name is more explicit, preventing any potential confusion at a glance

Author: pH-7

src/Http.php

@@ -107,8 +107,7 @@ public static function getHeadersList(): array
      */
     public static function setHeaders(string|array $headers): void
     {
-        // Header already sent
-        if (static::isSent()) {
+        if (static::areHeadersSent()) {
             throw new Exception('Headers were already sent.');
         }
 
@@ -171,7 +170,7 @@ public static function getProtocol(): ?string
      *
      * @return bool TRUE if the headers were sent, FALSE if not.
      */
-    private static function isSent(): bool
+    private static function areHeadersSent(): bool
     {
         return headers_sent();
     }