ArrayIterator description: add tags and flesh out the description (#3933)

* Improving wording and add markup tags

* reference/spl/arrayiterator.xml Replace links with tags

Co-authored-by: Christoph M. Becker <[email protected]>

---------

Co-authored-by: Christoph M. Becker <[email protected]>

Author: mmalferov

reference/spl/arrayiterator.xml

@@ -11,13 +11,14 @@
    &reftitle.intro;
    <para>
     Allows the removal of elements, and the modification of
-    keys or values while iterating over Arrays or Objects.
+    keys or values while iterating over <type>array</type>s or <type>object</type>s.
    </para>
    <para>
-    When you want to iterate over the same array multiple times you need to
-    instantiate ArrayObject and let it create ArrayIterator instances that
-    refer to it either by using &foreach; or by calling its getIterator()
-    method manually. 
+    To iterate the same array more than once, it is recommended to
+    instantiate <classname>ArrayObject</classname> and use the
+    <classname>ArrayIterator</classname> instance either implicitly created when
+    using &foreach; to iterate over the array stored internally, or create one by
+    calling the <methodname>ArrayObject::getIterator</methodname> method manually.
    </para>
   </section>
 <!-- }}} -->
@@ -82,7 +83,10 @@
      <varlistentry xml:id="arrayiterator.constants.std-prop-list">
       <term><constant>ArrayIterator::STD_PROP_LIST</constant></term>
       <listitem>
-       <para>Properties of the object have their normal functionality when accessed as list (var_dump, foreach, etc.).</para>
+       <para>
+        Properties of the object have their normal functionality
+        when accessed as list (<function>var_dump</function>, &foreach;, etc.).
+       </para>
       </listitem>
      </varlistentry>