Docs: Update jQuery used for demos to 3.6.0

jQuery 1.12.4 misses some Core APIs that jQuery UI depends on and that are not
polyfilled in demos.

Gruntfile.js

@@ -286,8 +286,8 @@ grunt.initConfig( {
 				"jquery-simulate/jquery.simulate.js": "jquery-simulate/jquery.simulate.js",
 				"jquery-simulate/LICENSE.txt": "jquery-simulate/LICENSE.txt",
 
-				"jquery/jquery.js": "jquery-1.x/dist/jquery.js",
-				"jquery/LICENSE.txt": "jquery-1.x/LICENSE.txt",
+				"jquery/jquery.js": "jquery-3.x/dist/jquery.js",
+				"jquery/LICENSE.txt": "jquery-3.x/LICENSE.txt",
 
 				"jquery-1.8.0/jquery.js": "jquery-1.8.0/jquery.js",
 				"jquery-1.8.0/MIT-LICENSE.txt": "jquery-1.8.0/MIT-LICENSE.txt",

bower.json

@@ -39,7 +39,7 @@
 		"jquery-1.12.2": "jquery#1.12.2",
 		"jquery-1.12.3": "jquery#1.12.3",
 		"jquery-1.12.4": "jquery#1.12.4",
-		"jquery-1.x": "jquery#1.12.4",
+		"jquery-3.x": "jquery#3.6.0",
 		"jquery-2.0.0": "jquery#2.0.0",
 		"jquery-2.0.1": "jquery#2.0.1",
 		"jquery-2.0.2": "jquery#2.0.2",

external/jquery/LICENSE.txt

@@ -1,13 +1,4 @@
-Copyright jQuery Foundation and other contributors, https://jquery.org/
-
-This software consists of voluntary contributions made by many
-individuals. For exact contribution history, see the revision history
-available at https://github.com/jquery/jquery
-
-The following license applies to all parts of this software except as
-documented below:
-
-====
+Copyright OpenJS Foundation and other contributors, https://openjsf.org/
 
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the
@@ -27,10 +18,3 @@ NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-====
-
-All files located in the node_modules and external directories are
-externally maintained libraries used by this software which have their
-own licenses; we recommend you read them, as their terms may differ from
-the terms above.