runtime(nohlsearch): add missing loaded_hlsearch guard

related: #15039
closes: #15402

Signed-off-by: Maxim Kim <habamax@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/pack/dist/opt/nohlsearch/plugin/nohlsearch.vim b/runtime/pack/dist/opt/nohlsearch/plugin/nohlsearch.vim
index 8d99307..a2d766e 100644
--- a/runtime/pack/dist/opt/nohlsearch/plugin/nohlsearch.vim
+++ b/runtime/pack/dist/opt/nohlsearch/plugin/nohlsearch.vim
@@ -1,10 +1,16 @@
 " nohlsearch.vim: Auto turn off hlsearch
-" Last Change: 2024-06-19
+" Last Change: 2024-07-31
 " Maintainer: Maxim Kim <habamax@gmail.com>
 "
 " turn off hlsearch after:
 " - doing nothing for 'updatetime'
 " - getting into insert mode
+
+if exists('g:loaded_nohlsearch')
+    finish
+endif
+let g:loaded_nohlsearch = 1
+
 augroup nohlsearch
     au!
     noremap <Plug>(nohlsearch) <cmd>nohlsearch<cr>