Use pop-ups hover to show the grammar errors

[evandrocoan]

This could be a new option popup for "display_mode": "panel", setting. Then when I put the mouse over the grammar error, it show it on a pop-up. For example:

[gtarawneh]

Thanks for the suggestion. I'll look into implementing it.

[Kristinita]

@gtarawneh , If you will add this, please, leave "display_mode": "panel" (current behavior), as option.

Thanks.

[gtarawneh]

@Kristinita of course