sampledSetsFunctionObject/sampledSetsDict: Added an example of sampling on a line

src/sampling/sampledSet/sampledSetsFunctionObject/sampledSetsDict

+/*--------------------------------*- C++ -*----------------------------------*\
+| =========                 |                                                 |
+| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
+|  \\    /   O peration     | Version:  dev                                   |
+|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
+|    \\/     M anipulation  |                                                 |
+\*---------------------------------------------------------------------------*/
+
+functions
+{
+    // Example of sampling on a line
+    lines
+    {
+        type sets;
+
+        functionObjectLibs ("libsampling.so");
+
+        outputControl   outputTime;
+        setFormat       gnuplot;
+        fields          (p U);
+        interpolationScheme cellPoint;
+        sets
+        (
+            diagonal
+            {
+                type midPoint;
+
+                axis x;
+                start (-0.0206 -0.0254 -0.0005);
+                end (0.29 0.0254 0.0005);
+            }
+        );
+    }
+}