test-runner: "-a" option also stands for "--all"

In the options for most command-line tools, -a stands for --all, and so
it does for test-runner. Add --all to the option description before
--auto as it's a more common option.

tools/test-runner.c

diff --git a/tools/test-runner.c b/tools/test-runner.c
index 4617afc..a11dc01 100644
--- a/tools/test-runner.c
+++ b/tools/test-runner.c
@@ -1213,7 +1213,7 @@
 		"Usage:\n");
 	printf("\ttest-runner [options] [--] <command> [args]\n");
 	printf("Options:\n"
-		"\t-a, --auto             Find tests and run them\n"
+		"\t-a, --all,--auto       Find tests and run them\n"
 		"\t-b, --dbus             Start D-Bus system daemon\n"
 		"\t-s, --dbus-session     Start D-Bus session daemon\n"
 		"\t-d, --daemon           Start bluetoothd\n"