small patch to STD.pm

[Mark Lentczner]

This fixes a typo and enables X>>+<<X to be an operator...

        - MtnViewMark

Index: STD.pm
===================================================================
--- STD.pm      (revision 25009)
+++ STD.pm      (working copy)
@@ -1148,7 +1148,7 @@
     X [
     | <infix> X
     | <infix=infix_prefix_meta_operator> X
-    | <infix=infix_curcumfix_meta_operator> X
+    | <infix=infix_circumfix_meta_operator> X
     ]
     <!!{ $<O> = $<infix><O>; }>
     <!!lex1: 'cross'>