Clean up cpluspluscheck violation.

"typename" is a C++ keyword, so pg_upgrade.h fails to compile in C++.
Fortunately, there seems no likely reason for somebody to need to
do that.  Nonetheless, it's project policy that all .h files should
pass cpluspluscheck, so rename the argument to fix that.

Oversight in 57c081de; back-patch as that was.  (The policy requiring
pg_upgrade.h to pass cpluspluscheck only goes back to v12, but it
seems best to keep this code looking the same in all branches.)

src/bin/pg_upgrade/pg_upgrade.h

@@ -443,7 +443,7 @@ bool		check_for_data_types_usage(ClusterInfo *cluster,
 									   const char *base_query,
 									   const char *output_path);
 bool		check_for_data_type_usage(ClusterInfo *cluster,
-									  const char *typename,
+									  const char *type_name,
 									  const char *output_path);
 void		new_9_0_populate_pg_largeobject_metadata(ClusterInfo *cluster,
 													 bool check_mode);

src/bin/pg_upgrade/version.c

@@ -233,20 +233,20 @@ check_for_data_types_usage(ClusterInfo *cluster,
  *
  * If so, write a report to the given file name, and return true.
  *
- * typename should be a fully qualified type name.  This is just a
+ * type_name should be a fully qualified type name.  This is just a
  * trivial wrapper around check_for_data_types_usage() to convert a
  * type name into a base query.
  */
 bool
 check_for_data_type_usage(ClusterInfo *cluster,
-						  const char *typename,
+						  const char *type_name,
 						  const char *output_path)
 {
 	bool		found;
 	char	   *base_query;
 
 	base_query = psprintf("SELECT '%s'::pg_catalog.regtype AS oid",
-						  typename);
+						  type_name);
 
 	found = check_for_data_types_usage(cluster, base_query, output_path);