Core: Warn and fill jQuery.nodeName()

Fixes #246
Closes #301

src/core.js

@@ -100,3 +100,9 @@ migrateWarnProp( jQuery.expr, "filters", jQuery.expr.pseudos,
 	"jQuery.expr.filters is deprecated; use jQuery.expr.pseudos" );
 migrateWarnProp( jQuery.expr, ":", jQuery.expr.pseudos,
 	"jQuery.expr[':'] is deprecated; use jQuery.expr.pseudos" );
+
+// Prior to jQuery 3.2 there were internal refs so we don't warn there
+if ( jQueryVersionSince( "3.2.0" ) ) {
+	migrateWarnFunc( jQuery, "nodeName", jQuery.nodeName,
+	"jQuery.nodeName is deprecated" );
+}

test/core.js

@@ -301,6 +301,16 @@ QUnit.test( "jQuery.holdReady (warn only)", function( assert ) {
 	} );
 } );
 
+QUnit[ jQueryVersionSince( "3.2.0" ) ? "test" : "skip" ]( "jQuery.nodeName", function( assert ) {
+	assert.expect( 2 );
+
+	expectWarning( assert, "jQuery.nodeName", function() {
+		var div = document.createElement( "div" );
+
+		assert.equal( jQuery.nodeName( div, "div" ), true, "it's a div" );
+	})
+});
+
 TestManager.runIframeTest( "old pre-3.0 jQuery", "core-jquery2.html",
 	function( assert, jQuery, window, document, log ) {
 		assert.expect( 1 );

warnings.md

@@ -218,3 +218,9 @@ See jQuery-ui [commit](https://github.com/jquery/jquery-ui/commit/c0093b599fcd58
 **Cause:** The `.hover()` method is a shorthand for the use of the `mouseover`/`mouseout` events. It is often a poor user interface choice because it does not allow for any small amounts of delay between when the mouse enters or exits an area and when the event fires. This can make it quite difficult to use with UI widgets such as drop-down menus.  For more information on the problems of hovering, see the [hoverIntent plugin](http://cherne.net/brian/resources/jquery.hoverIntent.html).
 
 **Solution:** Review uses of `.hover()` to determine if they are appropriate, and consider use of plugins such as `hoverIntent` as an alternative. The direct replacement for `.hover(fn1, fn2)`, is `.on("mouseenter", fn1).on("mouseleave", fn2)`.
+
+### JQMIGRATE: jQuery.nodeName() is deprecated
+
+**Cause:** This public but never-documented method has been deprecated as of jQuery 3.2.0.
+
+**Solution:** Replace calls such as `jQuery.nodeName( elem, "div" )` with a test such as `elem.nodeName.toLowerCase() === "div"`.