Link UI: Placeholder text

[dhananjaykuber]

Fixes #56378

What?

Update the placeholder text to "Search for a Page/Post or type URL".

Why?

When users first open the Link UI it's not clear what they are meant to do. I have seen users who thought they were only able to enter URLs, and that it wouldn't work for draft pages/pages.

Testing Instructions

1. Click on 'Add Link' option in Toolbar
2. Check the placeholder text of search input is more clear

Screenshots or screencast

Before

After

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[getdave]

Thank you for the PR.

The problem is that this UI can be configured to search for other types such as Taxonomies and things like that. In that context this won't make much sense.

Perhaps you could make the test conditional?

Personally I would lean towards keeping things simple however - the original text is good.