bpo-35054: Add more index entries for symbols. (GH-10064)

diff --git a/Doc/reference/import.rst b/Doc/reference/import.rst
index 44b5b81..7c4f275 100644
--- a/Doc/reference/import.rst
+++ b/Doc/reference/import.rst
@@ -127,8 +127,8 @@
 ------------------
 
 .. index::
-    pair:: package; namespace
-    pair:: package; portion
+    pair: package; namespace
+    pair: package; portion
 
 A namespace package is a composite of various :term:`portions <portion>`,
 where each portion contributes a subpackage to the parent package.  Portions