Fixup of wording for #346

Author: pmai

doc/description.rst

@@ -16,7 +16,7 @@ existing fields should be set, unless not setting a field carries a
 specific meaning as indicated in the accompanying comment.
 
 All field numbers of 10000 and upward are available for user-specific
-extensions (i.e. custom fields), i.e. no future evolution of OSI will
+extensions (i.e. custom fields), so no future evolution of OSI will
 use field numbers of 10000 or above itself.
 
 Compatibility