runtime(racket): update Racket runtime files

This brings the included Racket runtime files to commit c41bc5a (indent
for[*]/lists with accumulator clause correctly, 2024-11-12) of
https://github.com/benknoble/vim-racket.

Note that not all files from that repository are included.

closes: #16046

Signed-off-by: D. Ben Knoble <ben.knoble+github@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/ftplugin/racket.vim b/runtime/ftplugin/racket.vim
index 7bfd87d..52768d6 100644
--- a/runtime/ftplugin/racket.vim
+++ b/runtime/ftplugin/racket.vim
@@ -3,7 +3,7 @@
 " Maintainer:           D. Ben Knoble <ben.knoble+github@gmail.com>
 " Previous Maintainer:  Will Langstroth <will@langstroth.com>
 " URL:                  https://github.com/benknoble/vim-racket
-" Last Change:          2024 May 28
+" Last Change:          2024 Jun 01
 
 if exists("b:did_ftplugin")
   finish
@@ -16,19 +16,20 @@
 " quick hack to allow adding values
 setlocal iskeyword=@,!,#-',*-:,<-Z,a-z,~,_,94
 
+setlocal shiftwidth=2 softtabstop=2
+
 " Enable auto begin new comment line when continuing from an old comment line
 setlocal comments=:;;;;,:;;;,:;;,:;
 setlocal formatoptions+=r
 
-"setlocal commentstring=;;\ %s
-setlocal commentstring=#\|\ %s\ \|#
+setlocal commentstring=;;\ %s
 
 setlocal formatprg=raco\ fmt
 
 " Undo our settings when the filetype changes away from Racket
 " (this should be amended if settings/mappings are added above!)
 let b:undo_ftplugin =
-      \  "setlocal iskeyword< lispwords< lisp< comments< formatoptions< formatprg<"
+      \  "setlocal iskeyword< shiftwidth< softtabstop< comments< formatoptions< formatprg<"
       \. " | setlocal commentstring<"
 
 if !exists("no_plugin_maps") && !exists("no_racket_maps")