Generic/RequireStrictTypes: improve docs based on PR review suggestions

Author: rodrigoprimo

src/Standards/Generic/Docs/PHP/RequireStrictTypesStandard.xml

@@ -7,23 +7,16 @@
     <code_comparison>
         <code title="Valid: strict_types declaration is present.">
         <![CDATA[
-<?php
 declare(<em>strict_types=1</em>);
 
-<?php
-declare(ticks=1, <em>strict_types=1</em>);
-
-<?php
-declare(<em>strict_types=0</em>);
+declare(encoding='UTF-8', <em>strict_types=0</em>);
         ]]>
         </code>
         <code title="Invalid: Missing strict_types declaration.">
         <![CDATA[
-<?php
 declare(encoding='ISO-8859-1'<em></em>);
 
-<?php
-declare(strict_types=<em>0</em>);
+declare(ticks=1<em></em>);
         ]]>
         </code>
     </code_comparison>
@@ -35,16 +28,11 @@ declare(strict_types=<em>0</em>);
     <code_comparison>
         <code title="Valid: strict_types declaration is enabled.">
         <![CDATA[
-<?php
 declare(<em>strict_types=1</em>);
-
-<?php
-declare(ticks=1, <em>strict_types=1</em>);
         ]]>
         </code>
         <code title="Invalid: strict_types declaration is disabled.">
         <![CDATA[
-<?php
 declare(strict_types=<em>0</em>);
         ]]>
         </code>