Add git-wt config

Author: kachick

home-manager/git.nix

@@ -145,6 +145,10 @@ in
         root = "~/repos";
       };
 
+      wt = {
+        basedir = "../{gitroot}/.worktrees";
+      };
+
       # `git config --get-regexp ^alias` will show current aliases
       alias = {
         fixup = "commit --all --amend";

overlays/default.nix

@@ -69,6 +69,7 @@
         }
       );
 
+      # Don't enable shell integrations, it replaces original `git` command.
       git-wt = prev.unstable.git-wt.overrideAttrs (
         finalAttrs: previousAttrs: {
           # 0.15.0 or later is required to enable https://github.com/k1LoW/git-wt/pull/81