feat(config): enhance CrateDocs MCP server configuration

- Changed `ExecStart` to bind the server to `127.0.0.1` and added explicit `http` scheme.
- Removed unnecessary trailing whitespace across the file for cleaner formatting.

config.nix

@@ -32,7 +32,7 @@ in
       wantedBy = [ "multi-user.target" ];
 
       serviceConfig = {
-        ExecStart = "${lib.getExe pkgs.cratedocs-mcp} --port ${toString cfg.port}";
+        ExecStart = "${lib.getExe pkgs.cratedocs-mcp} http -a 127.0.0.1:${toString cfg.port}";
         Restart = "always";
         User = cfg.user;
         Group = cfg.group;