Remove function names from error messages

They are not necessary, and having them there gives useless work for
translators.

src/backend/access/transam/xlogfuncs.c

@@ -465,7 +465,8 @@ pg_walfile_name_offset(PG_FUNCTION_ARGS)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("recovery is in progress"),
-				 errhint("pg_walfile_name_offset() cannot be executed during recovery.")));
+				 errhint("%s cannot be executed during recovery.",
+						 "pg_walfile_name_offset()")));
 
 	/*
 	 * Construct a tuple descriptor for the result row.  This must match this
@@ -521,7 +522,8 @@ pg_walfile_name(PG_FUNCTION_ARGS)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("recovery is in progress"),
-				 errhint("pg_walfile_name() cannot be executed during recovery.")));
+				 errhint("%s cannot be executed during recovery.",
+						 "pg_walfile_name()")));
 
 	XLByteToPrevSeg(locationpoint, xlogsegno, wal_segment_size);
 	XLogFileName(xlogfilename, ThisTimeLineID, xlogsegno, wal_segment_size);

src/backend/commands/extension.c

@@ -2348,8 +2348,8 @@ pg_extension_config_dump(PG_FUNCTION_ARGS)
 	if (!creating_extension)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("pg_extension_config_dump() can only be called "
-						"from an SQL script executed by CREATE EXTENSION")));
+				 errmsg("%s can only be called from an SQL script executed by CREATE EXTENSION",
+						"pg_extension_config_dump()")));
 
 	/*
 	 * Check that the table exists and is a member of the extension being