Implement case insensitive, fix word disappearing bug

Use regex for case insesitive finding, implement String instead of char<Vec>, fix word disappearing by recalculating the render x for preview text

tui/src/confirmation.rs

@@ -119,8 +119,8 @@ impl FloatContent for ConfirmPrompt {
             Box::new([
                 Shortcut::new("Continue", ["Y", "y"]),
                 Shortcut::new("Abort", ["N", "n", "q", "Esc"]),
-                Shortcut::new("Scroll up", ["k", "Up"]),
-                Shortcut::new("Scroll down", ["j", "Down"]),
+                Shortcut::new("Scroll up", ["k"]),
+                Shortcut::new("Scroll down", ["j"]),
                 Shortcut::new("Close linutil", ["CTRL-c"]),
             ]),
         )