Arm toolchain wizard, explicit AArch64 mention

Author: ilg-ul

plugins/org.eclipse.embedcdt.managedbuild.cross.arm.ui/src/org/eclipse/embedcdt/internal/managedbuild/cross/arm/ui/messages.properties

@@ -14,7 +14,9 @@
 ###############################################################################
 
 SetCrossCommandWizardPage_browse=Browse...
-SetCrossCommandWizardPage_description=Select the toolchain and configure path
+SetCrossCommandWizardPage_description=\
+Select the toolchain and configure path. AArch64 projects require an AArch64 toolchain!
+
 SetCrossCommandWizardPage_name=GNU Arm Cross Command Wizard Page
 SetCrossCommandWizardPage_toolchain=Toolchain name:
 SetCrossCommandWizardPage_prefix=Compiler command: