Small doc fix: `make check` runs the tests (#469)

diff --git a/test/shaping/README.md b/test/shaping/README.md
index a581a34..d1df634 100644
--- a/test/shaping/README.md
+++ b/test/shaping/README.md
@@ -31,7 +31,7 @@
 ```
 
 If you created a new test file, add it to `Makefile.am` so it is run.
-Check that `make test` does indeed run it, and that the test passes.
+Check that `make check` does indeed run it, and that the test passes.
 When everything looks good, `git add` the new font as well as new
 test file if you created any.  You can see what new files are there
 by running `git status tests fonts/sha1sum`.  And commit!