messages/error mesages not shown on the activation page

[magnus78]

do_action( 'template_notices' ); isn't used on the activation page, so messages are not shown. The code does add messages such as

• your account is now active
• the account is already active

This makes the page confusing when you click on the activation link a second time, and is asked for an activation key...

[magnus78]

proposed fix

[DJPaul]

Need to review the issue, but it has a patch.

[johnjamesjacoby]

(In [6662]) Make sure notices appear in activation templates. Props magnus78. Fixes #4725.