Fix Stylesheet Mime type keeping b/c

[PhilETaylor]

Pull Request for Issue #16266.

Summary of Changes

Ensure b/c and ensure mime type is set on XML Stylesheets in RSS Feeds without PHP undefined index error.

Steps to replicate,

• Edit /libraries/joomla/document/feed.php
• On Line 206 (or anywhere in the render function, this is just to break it) add code:

// 3/4 style with no options or attribs
$this->addStyleSheet('/media/system/css/modal.css');

or

// 3 with mime specified
$this->addStyleSheet('/media/system/css/modal.css','text/css');

or

// Joomla 4 with type specified
$this->addStyleSheet('/media/system/css/modal.css',array(),array('type'=>'text/css'));

• View any RSS feed created by your Joomla site (mine: E.g.: index.php?option=com_content&view=featured&Itemid=109&format=feed&type=rss)

• see error message in the RSS of:

Then Apply this PR,

Expected result

No error

@810

[brianteeman]

what change in 3.7 introduced this "error"? Surely we should be reviewing what broke things before coding solutions. Perhaps the thing thhat broke this broke something else as well which hasnt been reported yet

[810]

I have tested this item ✅ successfully on 3593f5c

---

_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/16284.}

[810]

We will change it before J4.

thnx for the fix

[810]

I have tested this item ✅ successfully on f6008d9

---

_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/16284.}

[ghost]

I have tested this item ✅ successfully on f6008d9

---

_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/16284.}

[ghost]

RTC after two successful tests.