Add mvc: prefix to mapping samples in ref docs

Add 'mvc:' namespace prefix to 'mapping' and 'exclude-mapping' elements
in the reference documentation.

Issue: SPR-10670

src/reference/docbook/mvc.xml

@@ -5072,12 +5072,12 @@ public class WebConfig extends WebMvcConfigurerAdapter {
       <programlisting language="xml">&lt;mvc:interceptors&gt;
     &lt;bean class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor" /&gt;
     &lt;mvc:interceptor&gt;
-        &lt;mapping path="/**"/&gt;
-        &lt;exclude-mapping path="/admin/**"/&gt;
+        &lt;mvc:mapping path="/**"/&gt;
+        &lt;mvc:exclude-mapping path="/admin/**"/&gt;
         &lt;bean class="org.springframework.web.servlet.theme.ThemeChangeInterceptor" /&gt;
     &lt;/mvc:interceptor&gt;
     &lt;mvc:interceptor&gt;
-        &lt;mapping path="/secure/*"/&gt;
+        &lt;mvc:mapping path="/secure/*"/&gt;
         &lt;bean class="org.example.SecurityInterceptor" /&gt;
     &lt;/mvc:interceptor&gt;
 &lt;/mvc:interceptors&gt;