Fix dynamic clock icon (#2120)

* Fix dynamic clock icon

* Use printf variable scope

* shfmt do not like spaces

lib/command_duration.bash

@@ -11,7 +11,10 @@ function _command_duration_pre_exec() {
 }
 
 function _dynamic_clock_icon {
-	local -i clock_hand=$(((${1:-${SECONDS}} % 12) + 90))
+	local clock_hand
+	# clock hand value is between 90 and 9b in hexadecimal.
+	# so between 144 and 155 in base 10.
+	printf -v clock_hand '%x' $(((${1:-${SECONDS}} % 12) + 144))
 	printf -v 'COMMAND_DURATION_ICON' '%b' "\xf0\x9f\x95\x$clock_hand"
 }