Search suggest source delete actions are keyboard-unreachable and not announced

Steps to Reproduce:
1. Log in as admin and go to Administration, Search Suggest section.
2. Hover the mouse over a source (for example "Page titles"): a red X delete button appears at the right of the source header.
3. Move the mouse away: the X disappears (its container is display none until hover).
4. Now use only the keyboard: press Tab through the whole page. Focus never lands on X
5. With a screen reader (NVDA), browse the sources list: each delete control is announced as a bare "link" with no purpose.

Expected Results:

• The delete actions are reachable and operable by keyboard. Also they are readable.

Actual Results:

• Keyboard users can never reach "X" red button
• The "X" red button is not readable by NVDA (Assistive technologies announce 8 consecutive nameless "link" elements, giving no indication which source each one deletes.)