runtime(dist/vim9): fix regressions in dist#vim9#Open

fixes: #16533
fixes: #16532
closes: #16535

Signed-off-by: Luca Saccarola <github.e41mv@aleeas.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/plugin/openPlugin.vim b/runtime/plugin/openPlugin.vim
index 103b33c..c231dc4 100644
--- a/runtime/plugin/openPlugin.vim
+++ b/runtime/plugin/openPlugin.vim
@@ -12,9 +12,18 @@
 
 const no_gx = get(g:, "nogx", get(g:, "netrw_nogx", false))
 if !no_gx
+  def GetWordUnderCursor(): string
+    const url = matchstr(expand("<cWORD>"), '\%(\%(http\|ftp\|irc\)s\?\|file\)://\S\{-}\ze[^A-Za-z0-9/]*$')
+    if !empty(url)
+      return url
+    endif
+
+    const user_var = get(g:, 'gx_word', get(g:, 'netrw_gx', '<cfile>')
+    return expand(user_var)
+  enddef
+
   if maparg('gx', 'n') == ""
-    const file = get(g:, 'netrw_gx', '<cfile>')
-    nnoremap <unique> gx <scriptcmd>vim9.Open(expand(file))<CR>
+    nnoremap <unique> gx <scriptcmd>vim9.Open(GetWordUnderCursor())<CR>
   endif
   if maparg('gx', 'x') == ""
     xnoremap <unique> gx <scriptcmd>vim9.Open(getregion(getpos('v'), getpos('.'), { type: mode() })->join())<CR>