Redmine

Since r25030, user mentions in the web UI are displayed in three different ways as described in #39528#note-12. A mention of yourself has an orange background, a mention of another user who can view the object has a blue background, and a mention of a user who cannot view it and will not be notified has no background. This patch applies the same highlighting to email notifications.

Currently, mentions in email notifications are shown as plain links with no background color. The HTML emails already have the "user-current" and "user-mentionable" CSS classes, but the email layout has no styles for them. The patch adds the same styles as the web UI to the email layout, making mentions in email notifications consistent with the web UI.