2nd round review feedback from rmustacc.

@@ -25,11 +25,11 @@
 Within these various declarations, we have the following field types:
 
 <envs>    This is a list of compilation environments where the symbol
           should be legal.  To indicate that the symbol must not be legal
           an environment group can be prefixed with "-".  For example,
-          "SUS -SUSv4+" indicates a symbol that is legal in all SUS
+          "SUS+ -SUSv4+" indicates a symbol that is legal in all SUS
           environments up to SUSv3, and was removed in SUSv4 and subsequent
           versions of SUS.  As you can see, we can list multiple environments
           or environment groups, and we can add or remove to previous groups
           with subsequent ones.