Update core 8.3.0

web/vendor/zendframework/zend-feed/doc/book/find-feeds.md

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+# Feed Discovery from Web Pages
+
+Web pages often contain `<link>` tags that refer to feeds with content relevant
+to the particular page. `Zend\Feed\Reader\Reader` enables you to retrieve all
+feeds referenced by a web page with one method call:
+
+```php
+$feedLinks = Zend\Feed\Reader\Reader::findFeedLinks('http://www.example.com/news.html');
+```
+
+> ## Finding feed links requires an HTTP client
+>
+> To find feed links, you will need to have an [HTTP client](zend.feed.http-clients)
+> available. 
+>
+> If you are not using zend-http, you will need to inject `Reader` with the HTTP
+> client. See the [section on providing a client to Reader](http-clients.md#providing-a-client-to-reader).
+
+Here the `findFeedLinks()` method returns a `Zend\Feed\Reader\FeedSet` object,
+which is in turn a collection of other `Zend\Feed\Reader\FeedSet` objects, each
+referenced by `<link>` tags on the `news.html` web page.
+`Zend\Feed\Reader\Reader` will throw a
+`Zend\Feed\Reader\Exception\RuntimeException` upon failure, such as an HTTP
+404 response code or a malformed feed.
+
+You can examine all feed links located by iterating across the collection:
+
+```php
+$rssFeed = null;
+$feedLinks = Zend\Feed\Reader\Reader::findFeedLinks('http://www.example.com/news.html');
+foreach ($feedLinks as $link) {
+    if (stripos($link['type'], 'application/rss+xml') !== false) {
+        $rssFeed = $link['href'];
+        break;
+}
+```
+
+Each `Zend\Feed\Reader\FeedSet` object will expose the `rel`, `href`, `type`,
+and `title` properties of detected links for all RSS, Atom, or RDF feeds. You
+can always select the first encountered link of each type by using a shortcut:
+the first encountered link of a given type is assigned to a property named after
+the feed type.
+
+```php
+$rssFeed = null;
+$feedLinks = Zend\Feed\Reader\Reader::findFeedLinks('http://www.example.com/news.html');
+$firstAtomFeed = $feedLinks->atom;
+```