history-substring-search: update to upstream version 2019-05-12

Updates OMZ's copy to commit 0f80b8eb3368b46e5e573c1d91ae69eb095db3fb from zsh-users/zsh-history-substring-search

plugins/history-substring-search/history-substring-search.plugin.zsh

-# This file integrates the zsh-history-substring-search script into oh-my-zsh.
-
-source "${0:r:r}.zsh"
-
-if test "$CASE_SENSITIVE" = true; then
-  unset HISTORY_SUBSTRING_SEARCH_GLOBBING_FLAGS
-fi
-
-if test "$DISABLE_COLOR" = true; then
-  unset HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_FOUND
-  unset HISTORY_SUBSTRING_SEARCH_HIGHLIGHT_NOT_FOUND
-fi
+0=${(%):-%N}
+source ${0:A:h}/zsh-history-substring-search.zsh
 
 
 # Bind terminal-specific up and down keys
-# Bind in both emacs and vi modes so it works in both, and is not
-# sensitive to whether this is loaded before or after the vi-mode plugin
+
 if [[ -n "$terminfo[kcuu1]" ]]; then
   bindkey -M emacs "$terminfo[kcuu1]" history-substring-search-up
   bindkey -M viins "$terminfo[kcuu1]" history-substring-search-up