We were using a "push" div in order to force the footer to the bottom,
and were using a wrapper with a minimum height and negative margins.
The same thing can be accomplished using flex and making the wrapper
fill the empty space, which in my humble opinion simplifies the code and
makes it easier to follow.
We could further simplify the code by removing the wrapper div or the
footer wrapper, although I'm not sure the benefits overcome potential
inconveniences caused to other institutions who might have custom styles
based on the existence of these wrappers.
While the browser gem is great, we don't need it in this case for such a
simple usage.
There are a few really small differences between this code and the old
one: matching `/MSIE/` will return true for Opera 12 and false for
certain versions of IE11. Since we're only rendering a comment for IE8
and below, we don't care about IE11, and Opera 12 is six years old and
its users won't be affected by the comment.
Note we're still using the browser gem because ahoy_matey depends on it,
but now it's an indirect dependency.
They do the exact same thing; however `html_safe` might confuse
developers into thinking it will make the HTML safe. Using `raw` makes
it clear that we're inserting the text without escaping it.
Sometimes we're interpolating a link inside a translation, and marking
the whole translations as HTML safe.
However, some translations added by admins to the database or through
crowdin are not entirely under our control.
Although AFAIK crowdin checks for potential cross-site scripting
attacks, it's a good practice to sanitize parts of a string potentially
out of our control before marking the string as HTML safe.
Internet Explorer 9 was released eight years ago. Besides that, we don't
really support IE8 anyway, since we show a popup to IE8 users saying
we don't support it, we haven't maintained the IE8-specific CSS file for
years, and we don't test our JavaScript against IE8.
