Ignore commands that start with a space.

This is useful when you want to use a dangerous command, as it won't be
available with history searching.

lib/history.zsh

@@ -10,6 +10,7 @@ setopt hist_verify
 setopt inc_append_history
 setopt extended_history
 setopt hist_expire_dups_first
+setopt hist_ignore_space
 
 setopt SHARE_HISTORY
 setopt APPEND_HISTORY