Refactor check text area

- Adds missing trailing semicolons (";")
- Refactors copied styles iteration. 
- Adds "border-radius" and "resize" to fully match the existing text-area.
- Outdents the last half of the function.
- Removes “background-color” to allow CSS textarea highlight in spell check mode.
- Updates message & color while awaiting AJAX spell check response.
- Exits spell check mode when ESC key is pressed.