fix(bureau): fix top line space computation

Takes into account $ZLE_RPROMPT_INDENT and doesn't add the extra
space at the end so it doesn't bleed into the next line.

themes/bureau.zsh-theme

@@ -103,15 +103,10 @@ get_space () {
   local STR=$1$2
   local zero='%([BSUbfksu]|([FB]|){*})'
   local LENGTH=${#${(S%%)STR//$~zero/}}
-  local SPACES=""
-  (( LENGTH = ${COLUMNS} - $LENGTH - 1))
+  local SPACES=$(( COLUMNS - LENGTH - ${ZLE_RPROMPT_INDENT:-1} ))
 
-  for i in {0..$LENGTH}
-    do
-      SPACES="$SPACES "
-    done
-
-  echo $SPACES
+  (( SPACES > 0 )) || return
+  printf ' %.0s' {1..$SPACES}
 }
 
 _1LEFT="$_USERNAME $_PATH"