Using placeholders having similar (or identical) text as already present
as a label has a few issues.
First, it's a distraction. Reading the same information twice is
useless, requires an extra effort, and might even frustrate users.
Second, if users start typing before reading the placeholder and see it
disappear, they might think they're missing relevant information,
delete what they typed, and read the placeholder. That will get them
nowhere.
Finally, we display placeholders using a text offering very low contrast
against the background, so users don't think the placeholder is an
actual value entered in the field. Using such low contrast makes the
text hard to read, particularly for users with visual impairments.
So we're removing these placeholders.
This commit only deals with placeholder texts with similar (or
identical) texts as the label text. There might be other places where we
should replace placeholder texts with labels, but that's a different
topic.
Using `<a>` tags with no `href` means these elements cannot be activated
by keyboard users, so we're replacing them with buttons.
In the future we probably want to add more consistency so all toggle
buttons use the same code. We might also add styles depending on the
`aria-expanded` property.
Using the `_html` suffix in an i18n key is the same as using `html_safe`
on it, which means that translation could potentially be used for XSS
attacks.
Using the block syntax to generate the label with a <span> tag inside
isn't necessary after upgrading foundation_rails_helpers. Before the
upgrade, we couldn't do so because the <span> tag was escaped.
Not doing so caused crashes on applications which don't fall back to
English when a translation is missing.
We're adding them in a separate file so we can exclude it from crowdin
and so translators don't translate symbols as if they were words which
need translation.
