Update package name (#585)

Author: voltur01

docs/newlib.md

@@ -11,7 +11,7 @@ library variants is provided.
 ## Using pre-built `newlib` library package
 
 1. Install LLVM Embedded Toolchain for Arm
-1. Download corresponding `LLVMEmbeddedToolchainForArm-newlib-overlay` package
+1. Download corresponding `LLVM-ET-Arm-newlib-overlay` package
 and extract it on top of the main toolchain folder.
 
     * Note: The overlay package copies all the `newlib` library variants into the