Add shrink-to-fit to viewport meta tag

[ireade]

For responsive websites to be compatible with Safari in Split View, Apple recommends the addition of "shrink-to-fit=no" to the viewport meta tag (See iOS 9.1 doc)

<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">  

An article on why shrink-to-fit was added

May I submit a PR with this addition?

[paulirish]

AFAICT, it was added because people were using width=device-width, initial-scale=1 without understanding what they do.

my concern is that having shrink-to-fit in here would end up with the same result.

[warengonzaga]

got a good point!