msh: create testsuite (based on hush one)
hush: add TODO (doesn't know ":" command)

diff --git a/shell/msh_test/msh-bugs/syntax_err.right b/shell/msh_test/msh-bugs/syntax_err.right
new file mode 100644
index 0000000..08a270c
--- /dev/null
+++ b/shell/msh_test/msh-bugs/syntax_err.right
@@ -0,0 +1,2 @@
+shown
+hush: syntax error: unterminated '