Improve translating date format, user interaction

Problem/Motivation

(Noticed while reviewing #2161801: Update hook_help for Config translation module)

Steps to reproduce

install drupal
install (enable) configuration translation
add a language
go to translate any date format (like admin/config/regional/date-time/formats/manage/long/translate)
change the php format

After each character addition or deletion, a wait/autocomplete-like circle is in the input field, and after it updates the sample below, the curser is not in the input field

Proposed resolution

• Make a (1 second?) delay that allows changing of more than one character
• Have the curser be in the same place it was in the text area after the sample is updated

Remaining tasks

Figure out how to do this, javascript?

User interface changes

Yes. Fixing a UI bug.

API changes

No?