Adding PHP attributes

This is the first (small) step towards documenting enums - see doctrine#9304 (comment)
I started reading the page from the top, and did some minor changes.
Biggest change: If you agree, I'd continue adding php attributes to all code blocks.

docs/en/reference/basic-mapping.rst

@@ -14,17 +14,11 @@ After working through this guide you should know:
 Mapping of associations will be covered in the next chapter on
 :doc:`Association Mapping <association-mapping>`.
 
-Guide Assumptions
------------------
-
-You should have already :doc:`installed and configure <configuration>`
-Doctrine.
-
 Creating Classes for the Database
 ---------------------------------
 
 Every PHP object that you want to save in the database using Doctrine
-is called an "Entity". The term "Entity" describes objects
+is called an *Entity*. The term "Entity" describes objects
 that have an identity over many independent requests. This identity is
 usually achieved by assigning a unique identifier to an entity.
 In this tutorial the following ``Message`` PHP class will serve as the
@@ -50,28 +44,37 @@ that describes your entity.
 Doctrine provides several different ways to specify object-relational
 mapping metadata:
 
--  :doc:`Docblock Annotations <annotations-reference>`
 -  :doc:`Attributes <attributes-reference>`
+-  :doc:`Docblock Annotations <annotations-reference>`
 -  :doc:`XML <xml-mapping>`
--  :doc:`YAML <yaml-mapping>`
 -  :doc:`PHP code <php-mapping>`
+-  :doc:`YAML <yaml-mapping>` (deprecated and will be removed in version 3.0.)
 
 This manual will usually show mapping metadata via docblock annotations, though
 many examples also show the equivalent configuration in YAML and XML.
 
 .. note::
 
     All metadata drivers perform equally. Once the metadata of a class has been
-    read from the source (annotations, xml or yaml) it is stored in an instance
-    of the ``Doctrine\ORM\Mapping\ClassMetadata`` class and these instances are
+    read from the source (attributes, annotations, XML, etc.) it is stored in an instance
+    of the ``Doctrine\ORM\Mapping\ClassMetadata`` class which are
     stored in the metadata cache.  If you're not using a metadata cache (not
     recommended!) then the XML driver is the fastest.
 
 Marking our ``Message`` class as an entity for Doctrine is straightforward:
 
 .. configuration-block::
 
-    .. code-block:: php
+    .. code-block:: attribute
+
+        <?php
+        /** #[Entity] */
+        class Message
+        {
+            // ...
+        }
+
+    .. code-block:: annotation
 
         <?php
         /** @Entity */