Fix the "description" arg in VRT_blob() when used in .synth().

src/vmod_file.c

@@ -621,7 +621,7 @@ vmod_reader_synth(VRT_CTX, struct VPFX(file_reader) *rdr)
 
 	AN(rdr->flags & RDR_MAPPED);
 	AN(rdr->addr);
-	blob = VRT_blob(ctx, "VMOD file blob()", rdr->addr, rdr->info->len - 1,
+	blob = VRT_blob(ctx, "VMOD file synth()", rdr->addr, rdr->info->len - 1,
 			VMOD_FILE_BLOB_MAGIC);
 	VRT_synth_blob(ctx, blob);