Better guide users when deleting other users

[stefan.velthuys]

When deleting a user, you have to decide, if their content should be assigned to another person, or if that content should be deleted.

The option to delete the content is quite drastic, compared to assigning it.
Since this option is not reversible, it should be made clearer, what impact this has.

I see multiple ways to warn the users, what they're about to do:

• Mark the option to delete bold and use a different color (e.g. red)
• Users have to confirm in a second step, if the delete option is selected
• By default, pre-select the option to assign the content to another user
• Use a kind of "Danger Zone" like GitHub does for deleting repositories

But maybe, something as simple as showing the amount of content could suffice:

• Delete all content (19 posts, 2 pages, 31 images)

[ocean90]

Related: #20045, #23361

[hellofromTonya]

Hello @stefanvelthuys,

Welcome to WordPress Core's Trac! Thank you for opening this enhancement ticket with your suggestions to improve the user experience :)

I'm doing some ticket triage for contributor discoverability.

Changing the Version to 3.5.0 which is when the choice of content deletion or reassignment was introduced (see [22166]).