docs: add notes and descriptions for setting cookies

Author: kenjis

user_guide_src/source/helpers/cookie_helper.rst

@@ -42,6 +42,11 @@ The following functions are available:
     a description of its use, as this function is an alias for
     :php:meth:`CodeIgniter\\HTTP\\Response::setCookie()`.
 
+    .. note:: This helper function just sets browser cookies to the global response
+        instance that ``Services::response()`` returns. So, if you create and
+        return another response instance (e.g., if you call :php:func:`redirect()`),
+        the cookies set here will not be sent automatically.
+
 .. php:function:: get_cookie($index[, $xssClean = false[, $prefix = '']])
 
     :param    string    $index: Cookie name
@@ -78,6 +83,9 @@ The following functions are available:
     This function is otherwise identical to :php:func:`set_cookie()`, except that it
     does not have the ``value`` and ``expire`` parameters.
 
+    This also just sets browser cookies for deleting the cookies to the global
+    response instance that ``Services::response()`` returns.
+
     .. note:: When you use :php:func:`set_cookie()`,
         if the ``value`` is set to empty string and the ``expire`` is set to ``0``, the cookie will be deleted.
         If the ``value`` is set to non-empty string and the ``expire`` is set to ``0``, the cookie will only last as long as the browser is open.
@@ -95,4 +103,6 @@ The following functions are available:
     :param string $prefix: Cookie prefix
     :rtype: bool
 
-    Checks if a cookie exists by name. This is an alias of ``Response::hasCookie()``.
+    Checks if a cookie exists by name in the global response instance that
+    ``Services::response()`` returns. This is an alias of
+    :php:meth:`CodeIgniter\\HTTP\\Response::hasCookie()`.

user_guide_src/source/outgoing/response.rst

@@ -384,7 +384,9 @@ The methods provided by the parent class that are available are:
         .. note:: Prior to v4.2.7, the default values of ``$secure`` and ``$httponly`` were ``false``
             due to a bug, and these values from **app/Config/Cookie.php** were never used.
 
-        Sets a cookie containing the values you specify. There are two ways to
+        Sets a cookie containing the values you specify to the Response instance.
+
+        There are two ways to
         pass information to this method so that a cookie can be set: Array
         Method, and Discrete Parameters:
 
@@ -439,6 +441,8 @@ The methods provided by the parent class that are available are:
 
         Delete an existing cookie.
 
+        .. note:: This also just sets browser cookie for deleting the cookie.
+
         Only the ``name`` is required.
 
         The ``prefix`` is only needed if you need to avoid name collisions with