Minor changes -- mostly in comments -- plus one Unicode-related.

Conversion test cases.txt

@@ -770,9 +770,13 @@ a_tsal852ja$)@#%(!Ta)0daM)%!@sa
 // test special handing for @#
 @# #@ @a#
 
+// !!! We *don't* test X/~X here because they are known not to work.
+
 // English inserts
 rta'i [(of horse)] mgrin
-// It would be nice to have a test of the \ syntax, but that doesn't translate back to itself, so we can't pass it.
+
+// It would be really good to have a test of the \ syntax, but that 
+// doesn't translate back to itself, so we can't pass it.
 
 <?Reject?>
 
@@ -842,3 +846,6 @@ lng+ta
 // b+g+ka
 // a+ba
 // r+ra
+
+// This is legal in Unicode but not TMW:
+// b+'u