Make placeholder for the generator RFC compliant

[joker314]

Based on the security.txt RFC specification (section 3.4.2), the Contact: directive "MUST" follow RFC3986.

The value MUST follow the general syntax described in [RFC3986].
This means that "mailto" and "tel" URI schemes MUST be used when
specifying email addresses and telephone numbers.

Therefore,

- security@example.com
+ mailto:security@example.com

Upon Googling, I believe that this placeholder may be partially responsible for invalid security.txt files which specify emails without the mailto: scheme.

This pull request has not been tested.

[EdOverflow]

I think we used to automatically prefix the input with mailto: and this has since been removed from https://github.com/securitytxt/securitytxt.org/blob/master/js/genform.js. From a UX point of view, I am interested to know if it makes more sense requiring the user to type mailto: or have them submit their email address and let the JavaScript code do the prefixing. What would you suggest doing, @joker314?

[joker314]

@EdOverflow Would we do it like this: if the input contains a @ but does not start with https:// or http:// we prefix it with mailto; if it's fairly numeric we prefix it with tel:; and otherwise we error?

I think that could work, but another option is to have a dropdown to the left of the text input field, screenshot below:

[EdOverflow]

Oh, I love the sound of having a dropdown for the Contact: directive!

[joker314]

Does securitytxt.org have a minimum version of Internet Explorer it must support? I notice flexbox is already being used, I withdraw the question.

[joker314]

While there might be better solutions, this placeholder is misleading because it isn't valid, and could be contributing to the creation of noncompliant files. I suggest we merge this PR and then follow-up with e.g. a drop down? Do you agree @EdOverflow?

[EdOverflow]

Sounds good to me. :)