Fix GH-1919: Doc comment must start with /** followed by whitespace

While we're at it, we also fix the indentation of the example to match
common PHP formatting rules.

reference/reflection/reflectionclass/getdoccomment.xml

@@ -13,7 +13,7 @@
    <void/>
   </methodsynopsis>
   <para>
-   Gets doc comments from a class. Doc comments start with /**.
+   Gets doc comments from a class. Doc comments start with <literal>/**</literal>, followed by whitespace.
    If there are multiple doc comments above the class definition,
    the one closest to the class will be taken.
   </para>
@@ -40,12 +40,12 @@
     <programlisting role="php">
 <![CDATA[
 <?php
-/** 
-* A test class
-*
-* @param  foo bar
-* @return baz
-*/
+/**
+ * A test class
+ *
+ * @param  foo bar
+ * @return baz
+ */
 class TestClass { }
 
 $rc = new ReflectionClass('TestClass');
@@ -56,12 +56,12 @@ var_dump($rc->getDocComment());
     &example.outputs;
     <screen>
 <![CDATA[
-string(55) "/** 
-* A test class
-*
-* @param  foo bar
-* @return baz
-*/"
+string(61) "/** 
+ * A test class
+ *
+ * @param  foo bar
+ * @return baz
+ */"
 ]]>
     </screen>
    </example>