frontend: disable ssh ControlMaster prompts (autoask -> ask)

too nervy & seems to have no real advantage from any standpoint, esp. as
long as GPG Agent (my SSH agent) is not prompting & just letting apps
using my keys anyway

nix/nixos-modules/frontend/home.nix

@@ -347,7 +347,7 @@ in
 
     ssh = {
       enable = true;
-      controlMaster = "autoask";
+      controlMaster = "auto";
       controlPath = "~/.ssh/connections/%r@%h:%p";
       controlPersist = "10m";
       matchBlocks = {