patch 8.2.3368: not all Racket files are recognized

Problem:    Not all Racket files are recognized.
Solution:   Also recognize .rktl and .rktd files. (Doug Kearns)

runtime/filetype.vim

@@ -1623,7 +1623,7 @@ au BufNewFile,BufRead .zshrc,.zshenv,.zlogin,.zlogout,.zcompdump setf zsh
 au BufNewFile,BufRead *.zsh			setf zsh
 
 " Scheme
-au BufNewFile,BufRead *.scm,*.ss,*.rkt		setf scheme
+au BufNewFile,BufRead *.scm,*.ss,*.rkt,*.rktd,*.rktl 	setf scheme
 
 " Screen RC
 au BufNewFile,BufRead .screenrc,screenrc	setf screen

src/testdir/test_filetype.vim

@@ -428,7 +428,7 @@ let s:filename_checks = {
     \ 'sather': ['file.sa'],
     \ 'sbt': ['file.sbt'],
     \ 'scala': ['file.scala', 'file.sc'],
-    \ 'scheme': ['file.scm', 'file.ss', 'file.rkt'],
+    \ 'scheme': ['file.scm', 'file.ss', 'file.rkt', 'file.rktd', 'file.rktl'],
     \ 'scilab': ['file.sci', 'file.sce'],
     \ 'screen': ['.screenrc', 'screenrc'],
     \ 'sexplib': ['file.sexp'],

src/version.c

@@ -755,6 +755,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3368,
 /**/
     3367,
 /**/