Update node tag to say built-in instead of builtin (#6285)

For consistency the default case of the `node` tag is changed to `built-in` in Jelly. No localization has been done so no message bundles are affected.

core/src/main/resources/lib/hudson/node.jelly

@@ -37,7 +37,7 @@ THE SOFTWARE.
       ${valueStr}
     </j:when>
     <j:otherwise>
-      ${%builtin}
+      ${%built-in}
     </j:otherwise>
   </j:choose>
 </j:jelly>