Minor fixes: Media, Add Plugins, and Add Themes top toolbar inconsistencies

[afercia]

A few, minor, visual inconsistencies in these toolbars that would be nice to fix, see also the screenshot below:

• the right margin is different
• placeholders: title case or not title case?
• placeholders: ellipsis or not ellipsis?

About the ellipsis: it would be nice to reach some consensus and standardise across all the admin. I'd say remove them because they're useless and can be problematic for translations.

Side note: for accessibility, placeholders should not be used as replacement for labels but this should be discussed in a separate ticket.

Worth noting also the input fields size is a bit different, but just under a certain viewport size, I guess this is not a big deal.

[mikeviele]

Fixes Title casing of "Search Themes..." placeholder

[jamesacero]

Fixing search bar padding to match on all pages, removed ellipsis from placeholder text on all search bars

[mikeviele]

The ellipsis was not present in the current build as of the patch submission above (https://core.trac.wordpress.org/attachment/ticket/38010/38010.patch), but instead was converted to three periods (Search Themes...) with a comment stating

// placeholder (no ellipsis)

I opted to leave the the three periods in place.

[mattking5000]

for the sake of consistency, shouldn't the media library placeholder text be "Search Media" ?

[mikeviele]

Replying to mattking5000:

for the sake of consistency, shouldn't the media library placeholder text be "Search Media" ?

I agree that would be more consistent Matt. Not sure about the ellipses though. Current WP build uses 3 periods to "Search Themes..." so someone has looked at it. I'm not sure if we use "..." consistently across all placeholders like these or not.

[afercia]

For more details about the ellipses issue, see #32875. Basically, in some places there's the need to use three periods, so the inline comment // placeholder (no ellipsis) means don't use HTML entities or UTF-8 characters.

Changes to wp-admin/includes/class-walker-nav-menu-edit.php should be removed from the patch.

P.S.
The left padding should be preserved.

[mikeviele]

Thanks @afercia. I've updated with a new patch combining mine and @jamesacero 's work above.

[koenschipper]

I've tested it in Chrome and Safari. It all looks good. Contributor Day Wordcamp Netherlands :)

[dungengronovius]

Same result in Firefox, looks as expected

[afercia]

Checking all the currently used placeholders (including on the Customizer) in most of the cases they don't use title case and use the three dots. Let's standardise on this.

The refreshed patch also expands the Media search placeholder in Search media items... for consistency with the Plugins and Themes toolbars.

[afercia]

In 38795:

Administration: Better consistency for the Media, Add Plugins, and Add Themes toolbars.

Fixes the Add Themes toolbar padding. Standardizes the placeholders to no title
case and three trailing dots. Expands the Media search placeholder in
"Search media items..." for consistency with the Plugins and Themes toolbars.

Props mikeviele, jamesacero, mattking5000, koenschipper, dungengronovius.

Fixes #38010.