Fix typo

[SVN r65367]

Jamroot

@@ -93,7 +93,7 @@
 #   --python-buildid=ID     Adds the specified ID to the name of built
 #                           libraries that depend on Python.  The default 
 #                           is to not add anything. This ID is added in 
-#                           addition t --buildid.
+#                           addition to --buildid.
 #
 #
 #   --help                  This message.