Fix #13983. Switch to //# for sourcemaps.

Normally we'd avoid doing this on a patch release, but Chrome Canary is
spewing deprecation warnings already and that's generating bug tickets.
(cherry picked from commit d53ddc90)

Gruntfile.js

@@ -115,7 +115,7 @@ module.exports = function( grunt ) {
 						"/*! jQuery v<%= pkg.version %> | " +
 						"(c) 2005, 2013 jQuery Foundation, Inc. | " +
 						"jquery.org/license\n" +
-						"//@ sourceMappingURL=jquery.min.map\n" +
+						"//# sourceMappingURL=jquery.min.map\n" +
 						"*/\n"
 				}
 			}

build/release.js

@@ -166,10 +166,10 @@ function makeReleaseCopies( next ) {
 			} else if ( /\.min\.js$/.test( releaseFile ) ) {
 				// Minified files point back to the corresponding map;
 				// again assume one big happy directory.
-				// "//@ sourceMappingURL=jquery.min.map"
+				// "//# sourceMappingURL=jquery.min.map"
 				text = fs.readFileSync( builtFile, "utf8" )
-					.replace( /\/\/@ sourceMappingURL=\S+/,
-						"//@ sourceMappingURL=" + unpathedFile.replace( /\.js$/, ".map" ) );
+					.replace( /\/\/# sourceMappingURL=\S+/,
+						"//# sourceMappingURL=" + unpathedFile.replace( /\.js$/, ".map" ) );
 				fs.writeFileSync( releaseFile, text );
 			} else if ( builtFile !== releaseFile ) {
 				copy( builtFile, releaseFile );