Update _docs/tutorials/core/first_application_rtos/index.md

Co-authored-by: Ralph Lange <ralph-lange@users.noreply.github.com>

Author: pablogs9

_docs/tutorials/core/first_application_rtos/index.md

@@ -14,7 +14,7 @@ redirect_from:
 
 This tutorial is an entry point for using micro-ROS in one of the supported RTOSes: Nuttx, FreeRTOS, or Zephyr. The target hardware for this tutorial is the **[Olimex STM32-E407](https://www.olimex.com/Products/ARM/ST/STM32-E407/open-source-hardware)** evaluation board.
 
-First of all, make sure that you have a **ROS 2** environment and the **micro-ROS build system** installed in the computer. If not, please check  [**First micro-ROS application on Linux**](../first_application_linux/) tutorial in order to learn how to start with micro-ROS.
+First of all, make sure that you have a **ROS 2** environment and the **micro-ROS build system** installed in the computer. If not, please check the [**First micro-ROS application on Linux**](../first_application_linux/) tutorial in order to learn how to start with micro-ROS.
 
 The build system's workflow in the case of embedded systems is a four-step procedure: