switch elvish template to new try/catch syntax

'except' has been deprecated and replaced by 'catch' in elvish 0.18, and will be removed in 0.19

templates/elvish.txt

@@ -57,7 +57,7 @@ fn __zoxide_z {|@rest|
         var path
         try {
             set path = (zoxide query --exclude $pwd -- $@rest)
-        } except {
+        } catch {
         } else {
             __zoxide_cd $path
         }
@@ -70,7 +70,7 @@ fn __zoxide_zi {|@rest|
     var path
     try {
         set path = (zoxide query -i -- $@rest)
-    } except {
+    } catch {
     } else {
         __zoxide_cd $path
     }
@@ -116,4 +116,4 @@ set edit:completion:arg-completer[{{cmd}}] = $__zoxide_z_complete~
 #
 #   eval (zoxide init elvish | slurp)
 #
-# Note: zoxide only supports elvish v0.17.0 and above.
+# Note: zoxide only supports elvish v0.18.0 and above.