Update slider default value to 50.0 (#136)

Changed the initial value of the slider in the Demo component from 0.5 to 50.0 to better reflect the intended starting point.

Author: wheregmis

preview/src/components/slider/variants/main/mod.rs

@@ -4,7 +4,7 @@ use dioxus_primitives::slider::SliderValue;
 
 #[component]
 pub fn Demo() -> Element {
-    let mut current_value = use_signal(|| 0.5);
+    let mut current_value = use_signal(|| 50.0);
 
     rsx! {
         // Display the current value