Merge pull request #3386 from RonanSynnottArm/gnu

Add link for older Arm GNU Toolchain versions KBA

Author: pareenaverma

content/install-guides/gcc/arm-gnu.md

@@ -26,6 +26,8 @@ There are many versions of the [Arm GNU Toolchain](https://developer.arm.com/Too
 
 However there are reasons you may wish to use earlier compiler versions, so older versions are also available.
 
+See also [Where can I get older versions of the Arm GNU Toolchain and GCC for Arm Platforms?](https://developer.arm.com/documentation/ka005611/latest)
+
 ## Download the Arm GNU Toolchain {#download}
 
 Arm GNU Toolchain releases consist of cross toolchains for the following host operating systems:
@@ -171,4 +173,4 @@ Additional examples are included in the toolchain installation. If you installed
 ```console
 $HOME/arm-gnu-toolchain-15.2.rel1-aarch64-arm-none-eabi/share/doc/gcc-arm-none-eabi/examples
 ```
-You're now ready to use Arm GNU Toolchain.
+You're now ready to use Arm GNU Toolchain.