Don't use ‘add-zsh-hook’ for setting up vterm

It seems that the ‘autoload’ and ‘add-zsh-hook’ calls somehow interfered with
the later setup of the ‘zsh-autosuggestions’.

oni/home/services/emacs.scm

@@ -504,8 +504,10 @@
       "fi\n"
       (if (maybe-value-set? (home-emacs-vterm-configuration-buffer-name-string config))
           (string-append
-           "autoload -U add-zsh-hook\n"
-           "add-zsh-hook -Uz chpwd (){ print -Pn \"\\e]2;%m:%2~\\a\" }\n")
+           "vterm_chpwd(){ print -Pn \"\\e]2;%m:%2~\\a\" }\n"
+           "if [[ \"$INSIDE_EMACS\" = 'vterm' ]]; then\n"
+           "  chpwd_functions+=(vterm_chpwd)\n"
+           "fi\n")
           "")
       "vterm_prompt_end() {\n"
       "  vterm_printf \"51;A$(whoami)@$(hostname):$(pwd)\"\n"