Move PropertySlider to TS

src/style_manager/model/PropertySlider.js

@@ -1,10 +0,0 @@
-import Property from './PropertyNumber';
-
-export default class PropertySlider extends Property {
-  defaults() {
-    return {
-      ...Property.getDefaults(),
-      showInput: 1,
-    };
-  }
-}

src/style_manager/model/PropertySlider.ts

@@ -0,0 +1,10 @@
+import PropertyNumber from './PropertyNumber';
+
+export default class PropertySlider extends PropertyNumber {
+  defaults() {
+    return {
+      ...PropertyNumber.getDefaults(),
+      showInput: 1,
+    };
+  }
+}