Add spellcheck attribute for every input

[XieJiSS]

Hi, would you like to add HTML5 spellcheck attr for input nodes? I've recognized that sometimes the Dais misspell sanction to scantion thx

[CircuitCoder]

Seems worth doing to me. Added to the next milestone.

[dingjf-06]

I tested and think spellcheck does not work on Electron.