[Testing] Fixed the description of assertSelectorTextContains()

Author: javiereguiluz

testing.rst

@@ -212,9 +212,10 @@ Now you can use CSS selectors with the crawler. To assert that the phrase
 
     $this->assertSelectorTextContains('html h1.title', 'Hello World');
 
-This assertion will internally call ``$crawler->filter('html h1.title')``, which allows
-you to use CSS selectors to filter any HTML element in the page and check for
-its existence, attributes, text, etc.
+This assertion checks if the first element matching the CSS selector contains
+the given text. This asserts calls ``$crawler->filter('html h1.title')``
+internally, which allows you to use CSS selectors to filter any HTML element in
+the page and check for its existence, attributes, text, etc.
 
 The ``assertSelectorTextContains`` method is not a native PHPUnit assertion and is
 available thanks to the ``WebTestCase`` class.
@@ -223,15 +224,6 @@ available thanks to the ``WebTestCase`` class.
 
     The ``WebTestCase`` assertions were introduced in Symfony 4.3
 
-.. seealso::
-
-    Using native PHPUnit methods, the same assertion would look like this::
-
-        $this->assertGreaterThan(
-            0,
-            $crawler->filter('html h1.title:contains("Hello World")')->count()
-        );
-
 The crawler can also be used to interact with the page. Click on a link by first
 selecting it with the crawler using either an XPath expression or a CSS selector,
 then use the client to click on it::