docs(gauge): arc and circular (#271)

Author: marin-bratanov

_contentTemplates/gauges/additional-customization.md

@@ -14,4 +14,16 @@ To further customize the elements of the Radial Gauge you can use nested tags. W
 * Pointers
 #end
 
+#arc-gauge-additional-customization
+To further customize the elements of the Arc Gauge you can use nested tags. When configuring nested properties and child elements in your Arc Gauge, the inner tags will contain their parent tag name and add specifics to its end. In general the structure of such nested tags will be `<ArcGauge*Category**Specifics*>` where the **Category** can be one of the following:
 
+* Scale
+* GaugeArea
+#end
+
+#circular-gauge-additional-customization
+To further customize the elements of the Circular Gauge you can use nested tags. When configuring nested properties and child elements in your Circular Gauge, the inner tags will contain their parent tag name and add specifics to its end. In general the structure of such nested tags will be `<CircularGauge*Category**Specifics*>` where the **Category** can be one of the following:
+
+* Scale
+* GaugeArea
+#end