Hari's GSoC Spell Checking UI: Initial Implementation

[satti-hari-krishna-reddy]

This PR showcases the initial UI implementation for spell-checking with example data.

Next Steps:

• Refine UI interactions and improvements for enhanced usability based on feedback.

Recording.spell.checking.mp4

[satti-hari-krishna-reddy]

@jonorthwash Could you please review my pull request when you have a moment? Thank you!

[jonorthwash]

This is looking really good, just a couple minor things still need to be addressed:

1. Something that I brought up a couple weeks ago: the menu at the top has really weird spacing.
   

2. I'm not sure how I feel about center-justified suggestions. What do other spell checkers do?
   

3. Are "Spell Checker" (in the menu) and "Check" (on the button) localisable?