home-manager: improve the generation timestamp format

home-manager/home-manager

@@ -157,9 +157,9 @@ function doSwitch() {
 
 function doListGens() {
     pushd "/nix/var/nix/profiles/per-user/$USER" > /dev/null
-    ls --color=yes -gG --sort time home-manager-*-link \
+    ls --color=yes -gG --time-style=long-iso --sort time home-manager-*-link \
         | cut -d' ' -f 4- \
-        | sed -E 's/home-manager-([[:digit:]]*)-link/id \1/'
+        | sed -E 's/home-manager-([[:digit:]]*)-link/: id \1/'
     popd > /dev/null
 }