Doc: add note for generator

src/components/SvgChartV2/SvgChart.js

@@ -7,6 +7,21 @@ const Colors = {
   Default: '221,221,221',
 };
 
+/*
+        session: [[1585008000, 1585017000], [1585020600, 1585029600]]
+                    |                 |     /                /
+                    |                 |    /                /
+                    |                 |   /                /
+                    |                 |  /                /
+  value             |                 | /                /
+  18092.35 ..... (0,0) ------------------------------ (width, 0)
+                    |                                      |
+                    |                                      |
+                    |             SVG CHART                |
+                    |                                      |
+                    |                                      |
+  17402.93 ..... (0,height) ------------------------- (width,height)
+*/
 export const getGenerator = (pd, w, h, minX, maxX, minY, maxY, session, marginTop) => {
   const desession = x => {
     let res = x;