Fix elvish 0.18 compatibility

mods/file.elv

@@ -40,7 +40,7 @@ fn -s {|&sort=$false &type=exact @motive|
         $f $m | peach {|e|
           set result[$e] = $nil
         }
-      } except e { }
+      } catch e { }
     } $motive
   }
   -r $sort $result

mods/format.elv

@@ -38,7 +38,7 @@ fn int {|v|
       var n = (math:trunc $v)
       var s @_ = (str:split '.' (to-string $n))
       put $s
-    } except e {
+    } catch e {
       fail (printf '%s n’est pas un nombre' $v)
     }
   } elif (eq $k 'number') {