Add 'spellCheck={false}' to all relevant <input> components

[mkst]

Closes #1168. I dont have any spellchecking on the live site (using Chrome), so can someone confirm this change does what it should?

[marijnvdwerf]

Checked

• ✅ Scratch > Compiler options
• ✅ New Scratch > Diff label (already worked)
• ✅ Settings > Font Family
• ✅ Scratch > Diff options > Diff label

[mkst]

Search is top left on the main page.

Re: diff label, the code is there, this is what I see when i inspect the diff label input, spellcheck="false" is set:

[marijnvdwerf]

Ah, that one seems to already work properly on prod. I guess <input type="search"> acts differently.

SearchItem doesn't appear to be used at all in the codebase?