[libglnx/readme-libgsystem] Apply suggestion to README.md

[Will Thompson <wjt src gnome org>]

commit 76d18999a3a6afb7f49c6dabf884ec3a9bc3d6c0
Author: Will Thompson <will willthompson co uk>
Date:   Mon Dec 2 15:58:58 2019 +0000

    Apply suggestion to README.md

 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/README.md b/README.md
index d2cef5b..e9efa80 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-libglnx is the successor to [libgsystem]https://gitlab.gnome.org/Archive/libgsystem)
+libglnx is the successor to [libgsystem](https://gitlab.gnome.org/Archive/libgsystem)
 
 It is for modules which depend on both GLib and Linux, intended to be
 used as a git submodule.