[sms_ovh_http] improve description

[francesco-ooops]

Current USAGE file:

To configure this module, you need to:

Go to IAP menu

(settings > technical > IAP Account)

Create a new account with SMS OVH HTTP as provider Fill your account information

@sebastienbeau could you clarify what should be inputted in the following fields? I haven't found any "expeditor number" reference in OVH documentation

You can now send an sms

Great! :)

[francesco-ooops]

@sebastienbeau gentle reminder :)