docs: Alphabetize create cmd template options (#13993)

* Bugfix: Display template options for create command.

* Alphabetize "spack create" template options for readability

* Revert template choices format; alphabetize list

* flake8 fix

lib/spack/spack/cmd/create.py

@@ -427,7 +427,8 @@ def setup_parser(subparser):
         '-n', '--name',
         help="name of the package to create")
     subparser.add_argument(
-        '-t', '--template', metavar='TEMPLATE', choices=templates.keys(),
+        '-t', '--template', metavar='TEMPLATE',
+        choices=sorted(templates.keys()),
         help="build system template to use. options: %(choices)s")
     subparser.add_argument(
         '-r', '--repo',