PSR1/SideEffects: fix syntax error in XML documentation code example

Corrected a missing semicolon in the example code snippet.

Author: rodrigoprimo

src/Standards/PSR1/Docs/Files/SideEffectsStandard.xml

@@ -20,7 +20,7 @@ class Foo
 {
 }
 
-<em>echo "Class Foo loaded."</em>
+<em>echo "Class Foo loaded.";</em>
         ]]>
         </code>
     </code_comparison>