Add sidebar link to valueProp

Author: jarvelov

docs/SUMMARY.md

@@ -23,3 +23,4 @@
           * [props](api/ui-schema/field/field-options/props.md)
           * [slot](api/ui-schema/field/field-options/slot.md)
           * [style](api/ui-schema/field/field-options/style.md)
+        * [valueProp](api/ui-schema/field/value-prop.md)