xmobar: show forecast frost/snow/heat probabilities as icons

The bar's forecast line now uses Nerd Font weather glyphs instead of the
words, like the rain drop; the week notification keeps the words.

.config/xmobar/ens_brief.sh

@@ -47,9 +47,11 @@ if [ "$1" = "week" ]; then
 fi
 
 pick 1 2>/dev/null || exit 0
-read -r day temps rain <<< "${line#*: }"
+read -r day temps rain extra <<< "${line#*: }"
+# Probabilities as nf-weather icons: frost snowflake_cold, snow, heat hot
+extra=${extra//frost /$'\xee\x8d\xaf' } extra=${extra//snow /$'\xee\x8c\x9a' } extra=${extra//heat /$'\xee\x8d\xab' }
 label=""
 [[ $model != "${MODELS[0]}" ]] && label="${LABEL[$model]:-$model} "
 stale=""
 [[ ${line%%: *} == *STALE* ]] && stale=" <fc=#f7768e>!</fc>"
-echo "$label$day ${temps%C} "$''" $rain$stale"
+echo "$label$day ${temps%C} "$''" $rain${extra:+ $extra}$stale"