Update AATooltip.kt

charts/src/main/java/com/github/aachartmodel/aainfographics/aaoptionsmodel/AATooltip.kt

@@ -44,6 +44,7 @@ class AATooltip {
     var borderRadius: Number? = null
     var borderWidth: Number? = null
     var style: AAStyle? = null
+    var shape: String? = null
     var enabled: Boolean? = null
     var useHTML: Boolean? = null
     var formatter: String? = null
@@ -85,6 +86,11 @@ class AATooltip {
         return this
     }
 
+    fun shape(prop: String): AATooltip {
+        shape = prop
+        return this
+    }
+
     fun enabled(prop: Boolean?): AATooltip {
         enabled = prop
         return this