Makefile: Make `make test` silent

Makefile

@@ -44,7 +44,7 @@ purge: uninstall
 	rmdir -p --ignore-fail-on-non-empty $(DESTDIR)$(ZSHDIR)
 
 test:
-	if which git > /dev/null ; then :; else echo "'git' not found, exiting..."; exit 1; fi
+	@if which git > /dev/null ; then :; else echo "'git' not found, exiting..."; exit 1; fi
 
 moo:
 	@if [ -x /usr/games/cowsay ]; then /usr/games/cowsay "I hope you're happy now..."; fi