feat(chat): Support input suggestion modifiers #1854
                
     Merged
            
            
          
      
        
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This PR stacks on #1851 and adds support for keyboard modifiers to alter the input suggestion behavior:
Cmd/Ctrl+ (event) = force submittingAlt/Opt+ (event) = force setting without submittingI considered a shift modifier that would "do the opposite" but in practice that's confusing. It's much easier to learn one modifier per submit/don't submit.