Code block macros in JIRA comments can be created by specifying {code:<language>}my code...{code}

jira-javascript-code-block

{code:JavaScript}
grunt.loadNpmTasks('grunt-contrib-connect');
...
connect: {
	webServer: {
		options: {
			port: '<%= ports.webServer %>',
			base: '<%= buildDir %>',
			keepalive: false
		}
	}
}
...
grunt.registerTask('watch', [ 'build', 'karma:unit', 'connect:webServer', 'delta' ]);
{code}