runtime(vim): recognize <...> strings (and keys) for 'keywordprg'

see :help E499 and :h key-notation

closes: #16795

Signed-off-by: Konfekt <Konfekt@users.noreply.github.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/ftplugin/vim.vim b/runtime/ftplugin/vim.vim
index cf6ced9..99ce0bc 100644
--- a/runtime/ftplugin/vim.vim
+++ b/runtime/ftplugin/vim.vim
@@ -1,7 +1,7 @@
 " Vim filetype plugin
 " Language:          Vim
 " Maintainer:        Doug Kearns <dougkearns@gmail.com>
-" Last Change:       2025 Feb 25
+" Last Change:       2025 Mar 05
 " Former Maintainer: Bram Moolenaar <Bram@vim.org>
 " Contributors:      Riley Bruins <ribru17@gmail.com> ('commentstring'),
 "                    @Konfekt
@@ -85,6 +85,8 @@
       return ':'.topic
     elseif pre =~# '\<v:$'
       return 'v:'.topic
+    elseif pre =~# '<$'
+      return '<'.topic.'>'
     elseif pre =~# '\\$'
       return '/\'.topic
     elseif topic ==# 'v' && post =~# ':\w\+'