Fix comment typo in r321312.
Post-commit review by Kim Grasman!

llvm-svn: 321457
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 629037b..4c1d591 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -1550,7 +1550,7 @@
       // the enum-specifier. Each scoped enumerator is declared in the
       // scope of the enumeration.
       // For the case of unscoped enumerator, do not include in the qualified
-      // name any information about its enum enclosing scope, as is visibility
+      // name any information about its enum enclosing scope, as its visibility
       // is global.
       if (ED->isScoped())
         OS << *ED;