bug fix: %-expand POWERLEVEL9K_TIME_FORMAT on every prompt

reported in #77

internal/p10k.zsh

@@ -1903,17 +1903,18 @@ prompt_time() {
   if (( ! $+_P9K_TIME_TEXT )); then
     if [[ $POWERLEVEL9K_EXPERIMENTAL_TIME_REALTIME == true ]]; then
       _p9k_escape $POWERLEVEL9K_TIME_FORMAT
-      _P9K_TIME_TEXT=$_P9K_RETVAL
+      _P9K_TIME_TEXT=("" "$_P9K_RETVAL")
     else
-      _p9k_escape ${${(%)POWERLEVEL9K_TIME_FORMAT}//\%/%%}
-      _P9K_TIME_TEXT=$_P9K_RETVAL
-      if [[ $POWERLEVEL9K_TIME_UPDATE_ON_COMMAND == true ]]; then
       _p9k_escape $POWERLEVEL9K_TIME_FORMAT
-        _P9K_TIME_TEXT=\${_P9K_LINE_FINISH-$_P9K_TIME_TEXT}\${_P9K_LINE_FINISH+$_P9K_RETVAL}
+      if [[ $POWERLEVEL9K_TIME_UPDATE_ON_COMMAND == true ]]; then
+        _P9K_TIME_TEXT=("\${_P9K_LINE_FINISH-$_P9K_RETVAL}" "\${_P9K_LINE_FINISH+$_P9K_RETVAL}")
+      else
+        _P9K_TIME_TEXT=("$_P9K_RETVAL" "")
       fi
     fi
   fi
-  "$1_prompt_segment" "$0" "$2" "$DEFAULT_COLOR_INVERTED" "$DEFAULT_COLOR" "TIME_ICON" 1 '' "$_P9K_TIME_TEXT"
+  "$1_prompt_segment" "$0" "$2" "$DEFAULT_COLOR_INVERTED" "$DEFAULT_COLOR" "TIME_ICON" 1 '' \
+      "${(%)_P9K_TIME_TEXT[1]//\%/%%}${_P9K_TIME_TEXT[2]}"
 }
 
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