[json-glib] docs: Update the build instructions

[Emmanuele Bassi <ebassi src gnome org>]

commit 25a0de52bf369de0c264d88eea98c984f30fec75
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Mon Jul 10 16:26:27 2017 +0100

    docs: Update the build instructions

 README.md |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/README.md b/README.md
index f002fda..63543b6 100644
--- a/README.md
+++ b/README.md
@@ -43,10 +43,12 @@ To build JSON-GLib just run:
 ```sh
   $ meson _build .
   $ ninja -C _build
-  $ ninja -C _build test
-  # ninja -C _build install
+  $ mesontest -C _build
+  $ sudo ninja -C _build install
 ```
 
+See the [Meson documentation](http://mesonbuild.com) for more information.
+
 BUGS
 --------------------------------------------------------------------------------
 JSON-GLib tracks bugs in the GNOME Bugzilla.