refactor: use fewer calls to create now variable

instead of `20240422_1713802685`, use `20240422121805` and skip call to `awk`

Signed-off-by: Lucas Larson <[email protected]>

setup

@@ -37,7 +37,7 @@ cd -- "${HOME%/}" ||
   exit 1
 
 # save `date` for backup files
-now="$(command -p -- date -- '+%Y%m%d')"_"$(command -p -- awk -- 'BEGIN {srand(); print srand()}')"
+now="$(command -p -- date -- '+%Y%m%d%H%M%S')"
 
 # unset `$PS4`
 # if this quaternary prompt string is already unset, then