[dev] update scales article

Modernize code example and normalize formatting

Author: mlakatkou

docs/api/config/scales.md

@@ -16,24 +16,27 @@ description: "defines configuration settings of the time scale"
 
 ~~~jsx
 gantt.config.scales = [
-    {unit: "month", step: 1, format: "%F, %Y"},
-    {unit: "week", step: 1, format: function (date) {
-        return "Week #" + gantt.date.getWeek(date);
-    }},
-    {unit: "day", step: 1, format: "%D", css: function(date) {
-    if(!gantt.isWorkTime({ date: date, unit: "day"})){
-            return "weekend"
-        }
-    }}
+    { unit: "month", step: 1, format: "%F, %Y" },
+    {
+        unit: "week",
+        step: 1,
+        format: (date) => `Week #${gantt.date.getWeek(date)}`
+    },
+    {
+        unit: "day",
+        step: 1,
+        format: "%D",
+        css: (date) => !gantt.isWorkTime({ date, unit: "day" }) ? "weekend" : ""
+    }
 ];
 ~~~
 
 ### Details
 
 Each object in the array specifies a single scale. An object can take the following attributes:
 
-- **unit** - (*string*) - the name of the scale unit. The available values are: "minute", "hour", "day" (default), "week", "quarter", "month", "year". 
-There is also a possiblity to set a custom unit. Read more on the topic [here](guides/configuring-time-scale.md#customtimeunits).
+- **unit** - (*string*) - the name of the scale unit. The available values are: "minute", "hour", "day" (default), "week", "quarter", "month", "year".
+There is also a possibility to set a custom unit. Read more on the topic [here](guides/configuring-time-scale.md#customtimeunits).
 - **step?** - (*number*) - the step of the time scale (X-Axis), 1 by default.
 - **format? (date): any** - (*string | Function*) - the format of the scale's labels. If set as a function, expects a date object as a parameter.
     - **_date_** - (*Date*) - a date that will be converted