Generic/IncrementDecrementSpacing: add XML documentation

Author: rodrigoprimo

src/Standards/Generic/Docs/WhiteSpace/IncrementDecrementSpacingStandard.xml

@@ -0,0 +1,46 @@
+<documentation title="Increment Decrement Spacing">
+    <standard>
+    <![CDATA[
+    There should be no whitespaces between a pre-increment/pre-decrement operator and a variable.
+    ]]>
+    </standard>
+    <code_comparison>
+        <code title="Valid: No whitespaces between a pre-increment/pre-decrement operator and a variable.">
+        <![CDATA[
+++<em></em>$i;
+--<em></em>ClassName::$prop;
+--<em></em>$obj->prop;
+        ]]>
+        </code>
+        <code title="Invalid: Whitespaces found between a pre-increment/pre-decrement operator and a variable.">
+        <![CDATA[
+++<em> </em>$i;
+--<em>    </em>ClassName::$prop;
+--<em>
+</em>$obj->prop;
+        ]]>
+        </code>
+    </code_comparison>
+    <standard>
+    <![CDATA[
+    There should be no whitespaces between a variable and a post-increment/post-decrement operator.
+    ]]>
+    </standard>
+    <code_comparison>
+        <code title="Valid: No whitespaces between a variable and a post-increment/post-decrement operator.">
+        <![CDATA[
+<em></em>$i++;
+<em></em>ClassName::$prop++;
+<em></em>$obj->prop--;
+        ]]>
+        </code>
+        <code title="Invalid: Whitespaces found between a variable and a post-increment/post-decrement operator.">
+        <![CDATA[
+$i<em> </em>++;
+ClassName::$prop<em>    </em>++;
+$obj->prop<em>
+</em>--;
+        ]]>
+        </code>
+    </code_comparison>
+</documentation>