nixpkgs/elvish: fix use local error handling

.config/nixpkgs/elvish/lib/config.elv

@@ -1,3 +1,4 @@
+use str
 use prompt
 use nix-shell
 use direlv
@@ -41,7 +42,7 @@ eval (carapace _carapace|slurp)
 try {
   use local
 } catch e {
-  if (not-eq $e[reason] "<unknown no such module: local>") {
+  if (not (str:contains (to-string $e[reason]) "no such module")) {
     fail $e
   }
 }