Registration not possible if username contains hyphen
It's not possible to register at https://l10n.gnome.org/register/ if username contains a hyphen. Furthermore, the error message doesn't correspond to valid field and thus user might think the given email value contains errors.
From DL's pot file: #: people/forms.py:23 msgid "May contain only letters, numbers, underscores or hyphens"
Steps to reproduce:
- Go to registration page at https://l10n.gnome.org/register/
- Provide username with a hyphen in it
- Provide valid input into email address and password fields
- Click "Register with password"
- Face the error message (in red) "Provide a valid value"