Remove cursor highlighter from zimrc template

Not needed in MacOS iTerm and Terminal, (u)rxvt, termite, alacritty and
gnome-terminal.
Does it do any good in any situation?

Closes #337

The develop branch already has this out:
https://github.com/zimfw/install/blob/229cea08e5d2d6806c6bef837d67c2d7a1119744/src/templates/zimrc.zsh.erb#L83-L85

templates/zimrc

@@ -72,9 +72,7 @@ zinput_mode='emacs'
 # This determines what highlighters will be used with the syntax-highlighting module.
 # Documentation of the highlighters can be found here:
 #   https://github.com/zsh-users/zsh-syntax-highlighting/blob/master/docs/highlighters.md
-# For (u)rxvt, termite and gnome-terminal users,
-# removing the 'cursor' highlighter will fix the disappearing cursor problem
-zhighlighters=(main brackets cursor)
+zhighlighters=(main brackets)
 
 #
 # SSH