Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

This adds a new feature to `Flash` that allows to pin it after a
specified selector. This removes a fixed position from such award-emoji
alert, and makes it responsive by design of selector that this alert is
pinned to.

Closes #3996

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

* dont fadeout so user can read
* show inside content block so user can notice it

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>