Improve index entry for "import"; responding to comments by Stefan

Franke <sfranke@cdc-group.com>.

Doc/lib/libimp.tex

@@ -5,7 +5,7 @@
 \modulesynopsis{Access the implementation of the \keyword{import} statement.}
 
 
-This\kwindex{import} module provides an interface to the mechanisms
+This\stindex{import} module provides an interface to the mechanisms
 used to implement the \keyword{import} statement.  It defines the
 following constants and functions: