home: zsh: disable shared history

I know I just activated it, but I can't get used to it...

I would like to have a mixture of it:
* Be able to search across *all* shell histories when using Ctrl-r.
* Only go up/down my session's shell history when using Ctrl-n/Ctrl-p.

Enabling shared history gets me the first one, but means I can't limit
my up/down history to just the one session.

Disabling shared history means that I can't search across all shell
histories, but keeps my up/down history tidier.

All-in-all I like the second one better.

home/zsh/default.nix

@@ -34,7 +34,7 @@ in
         expireDuplicatesFirst = true;
         ignoreSpace = true;
         ignoreDups = true;
-        share = true;
+        share = false;
         path = "${config.xdg.dataHome}/zsh/zsh_history";
       };