minor #10945 Clarify using chained filterXPath (benito103e)

This PR was merged into the 3.4 branch.

Discussion
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Clarify using chained filterXPath

filterXpath() return a crawler that is considered as a fake parent of the elements inside it.
So we must re-specify the parent node to access direct children.

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Commits
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17e3d81 Clarify using chained filterXPath

Author: javiereguiluz

components/dom_crawler.rst

@@ -76,6 +76,17 @@ Node Filtering
 Using XPath expressions is really easy::
 
     $crawler = $crawler->filterXPath('descendant-or-self::body/p');
+    
+    // To chained "filterXPath" : be aware that filterXPath is evaluated in the context of the crawler
+    $crawler->filterXPath('parent')->each(function (Crawler $parentCrawler, $i) {
+        // NOK : Direct child can not be found
+        $childCrawler = $parentCrawler->filterXPath('child-tag/sub-child-tag');
+        
+        // OK : You must specify parent tag
+        $subChildCrawler = $parentCrawler->filterXPath('parent/child-tag/sub-child-tag');
+        $subChildCrawler = $parentCrawler->filterXPath('node()/child-tag/sub-child-tag');
+    });
+    
 
 .. tip::