Remove stray reference to pre-processing.

And fix a typo.

Author: handrews

jsonschema-hyperschema.xml

@@ -412,7 +412,7 @@
 
                     <section title="Values for substitution">
                         <t>
-                            After pre-processing, the URI Template is filled out using data from some combination of an externa source and the instance.
+                            The URI Template is filled out using data from some combination of an external source and the instance.
                             Where either instance data or external data may be used, this section will refer simply to "data" or to a "value".
                             When the source is important, it is specified explicitly.