patch 9.1.0987: filetype: cake files are not recognized

Problem:  filetype: cake files are not recognized
Solution: detect '*.cake' files as cs filetype
          (Zoe Roux)

References:
https://cakebuild.net/

closes: #16367

Signed-off-by: Zoe Roux <zoe.roux@zoriya.dev>
Signed-off-by: Christian Brabandt <cb@256bit.org>

Author: zoriya

runtime/filetype.vim

@@ -342,7 +342,7 @@ au BufNewFile,BufRead *.capnp			setf capnp
 au BufNewFile,BufRead cgdbrc			setf cgdbrc
 
 " C#
-au BufNewFile,BufRead *.cs,*.csx		setf cs
+au BufNewFile,BufRead *.cs,*.csx,*.cake		setf cs
 
 " CSDL
 au BufNewFile,BufRead *.csdl			setf csdl

src/testdir/test_filetype.vim

@@ -196,7 +196,7 @@ def s:GetFilenameChecks(): dict<list<string>>
     crm: ['file.crm'],
     crontab: ['crontab', 'crontab.file', '/etc/cron.d/file', 'any/etc/cron.d/file'],
     crystal: ['file.cr'],
-    cs: ['file.cs', 'file.csx'],
+    cs: ['file.cs', 'file.csx', 'file.cake'],
     csc: ['file.csc'],
     csdl: ['file.csdl'],
     csp: ['file.csp', 'file.fdr'],

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    987,
 /**/
     986,
 /**/