Incorporated the review comments

Author: rajkan01

docs/porting/target/tickless/resources/Tickless.png

@@ -18,11 +18,21 @@ To support tickless mode in Mbed OS, your target needs to meet two requirements:
 - Support for Sleep HAL API
 - Support for either Low Power or Microsecond Ticker HAL API
 
-To enable tickless mode for your target, add the `MBED_TICKLESS` macro in target.json > your target's section > macro options.
-
-When the tickless mode is enabled, the device default SysTick mechanism overrides by the [OsTimer](../mbed-os-api-doxy/structos__timer__def.html) implementation based on either the [low power ticker](../mbed-os-api-doxy/group__hal__lp__ticker.html) or [microsecond ticker](../mbed-os-api-doxy/group__hal__us__ticker.html).
-
-By default, tickless mode uses the low-power ticker (if available). If a target's low-power ticker has an excessively long wake-up time or other performance issues, make it use the microsecond ticker instead: set `tickless-from-us-ticker` to `true` in target.json > your target's section.
+To enable tickless mode for your target, add the `MBED_TICKLESS` macro in `target.json` of your target's section as follows:
+```json
+"macros_add": [
+    "MBED_TICKLESS"
+]
+```
+
+When the tickless mode is enabled, the device's default SysTick mechanism overrides by the [OsTimer](../mbed-os-api-doxy/structos__timer__def.html) implementation, based on either the [low power ticker](../mbed-os-api-doxy/group__hal__lp__ticker.html) or [microsecond ticker](../mbed-os-api-doxy/group__hal__us__ticker.html).
+
+By default, tickless mode uses the low power ticker (if available). If a target's low power ticker has an excessively long wake-up time or other performance issues, make it use the microsecond ticker instead by adding the below configuration in `target.json` of your target's section.
+```json
+"overrides": {
+    "tickless-from-us-ticker": true
+}
+```
 
 If tickless mode uses the microsecond ticker, the device will enter sleep rather than deep sleep, but will still avoid unnecessary tick calls.