[docs] fix formatting for GettingStarted.md and add needed flag for linux
[docs] fix formatting for GettingStarted.md and add needed flag for linux

roambotics/swift,roambotics/swift,roambotics/swift,roambotics/swift,roambotics/swift,apple/swift,apple/swift,apple/swift,apple/swift,roambotics/swift,apple/swift,apple/swift