Update platforms.md and _next-steps.md

Author: annietllnd

content/learning-paths/microcontrollers/iot-sdk/_next-steps.md

@@ -26,7 +26,7 @@ further_reading:
         link: https://devsummit.arm.com/flow/arm/devsummit22/sessions-catalog/page/sessions/session/16600464346670018mPQ
         type: website
     - resource:
-        title: Learn more about the Corstone platform
+        title: Learn more about the Corstone reference systems
         link: https://www.arm.com/products/silicon-ip-subsystems/
         type: website
 

content/learning-paths/microcontrollers/nav-mlek/platforms.md

@@ -19,7 +19,7 @@ MPS3 is the recommended solution for evaluating performance, but boards are in s
 
 ## Virtual Hardware
 
-Virtual implementations of the Corstone platforms are also available for software development. These can be accessed locally or in the cloud.
+Virtual implementations of the Corstone reference systems are also available for software development. These can be accessed locally or in the cloud.
 
 ### Ecosystem FVPs