docs for double.NaN suopport

Author: beto-rodriguez

docs/cartesianChart/axes.md

@@ -187,8 +187,7 @@ chartControl.UpdateStarted +=
 
 ## Clearing the current zooming or panning
 
-Setting `MinLimit` and `MaxLimit` properties to `null` will clear the current `zooming` or `panning`, and will let the chart fit the view
-of the chart to the available data in the chart, the default value of both properties is `null`.
+Setting `MinLimit` and `MaxLimit` properties to `null` or `double.NaN` will clear the current limits and fit the the data to the viewport.
 
 ## MinStep property
 

docs/cartesianChart/overview.md

@@ -429,8 +429,7 @@ method is called.
 
 ## Clearing the current zooming or panning
 
-Setting `MinLimit` and `MaxLimit` properties to `null` will clear the current `zooming` or `panning`, and will let the chart fit the view
-of the chart to the available data in the chart, the default value of both properties is `null`.
+Setting `MinLimit` and `MaxLimit` properties to `null` or `double.NaN` will clear the current limits and fit the the data to the viewport.
 
 {{ render this "~/shared/chart.md" }}
 

docs/samples/lines/zoom/template.md

@@ -99,8 +99,7 @@ the max and min visible limits of the axis, default is `null` and `null` means t
 
 # Clearing zooming and panning
 
-Setting the axes `MinLimit` and `MaxLimit` properties to `null` will clear the current `zooming` or `panning`, and will let the chart fit the view
-of the chart to the available data in the chart, for example:
+Setting `MinLimit` and `MaxLimit` properties to `null` or `double.NaN` will clear the current limits and fit the the data to the viewport.
 
 ```c#
 // where myChart is a reference to the chart in the UI

src/LiveChartsCore/Kernel/Sketches/IPlane.cs

@@ -115,7 +115,7 @@ public interface IPlane : IChartElement
 
     /// <summary>
     /// Gets or sets the minimum value visible in the axis, any point less than this value will be hidden, 
-    /// set it to null to use a value based on the smaller value in the chart.
+    /// set it to null (or double.NaN) to use a value based on the smaller value in the chart.
     /// </summary>
     /// <value>
     /// The minimum value.
@@ -124,7 +124,7 @@ public interface IPlane : IChartElement
 
     /// <summary>
     /// Gets or sets the maximum value visible in the axis, any point greater than this value will be hidden, 
-    /// set it null to use a value based on the greater value in the chart.
+    /// set it null (or double.NaN) to use a value based on the greater value in the chart.
     /// </summary>
     /// <value>
     /// The maximum value.