Indicate correct way to implement parsing in theory add-ons

Workaround for issue identified in github issue #1370

src/1/theory_tests/gh1370Script.sml

@@ -0,0 +1,15 @@
+open HolKernel boolLib
+
+val _ = new_theory"gh1370";
+
+val _ = new_definition ("def", “c = T”);
+
+val _ =
+ adjoin_to_theory
+ {sig_ps = SOME (fn _ => PP.add_string "val ctm : Term.term"),
+  struct_ps = NONE};
+
+val _ = adjoin_after_completion
+    (fn _ => PP.add_string ("val ctm = Parse.Term ‘c’;\n\n"))
+
+val _ = export_theory();

src/1/theory_tests/gh1370childScript.sml

@@ -0,0 +1,11 @@
+open HolKernel Parse boolLib
+
+open gh1370Theory
+
+val _ = new_theory "gh1370child";
+
+val _ = type_of gh1370Theory.ctm = bool andalso
+        (print "ctm has correct type\n";true) orelse
+        OS.Process.exit OS.Process.failure
+
+val _ = export_theory();