patch 8.2.2788: Raku is now the only name what once was called perl6

Problem:    Raku is now the only name what once was called perl6.
Solution:   Adjust the filetype detection. (closes #8120)

runtime/filetype.vim

@@ -1208,8 +1208,6 @@ else
   au BufNewFile,BufRead *.pl			call dist#ft#FTpl()
 endif
 au BufNewFile,BufRead *.plx,*.al,*.psgi		setf perl
-au BufNewFile,BufRead *.p6,*.pm6,*.pl6		setf perl6
-au BufNewFile,BufRead *.raku,*.rakumod		setf perl6
 
 " Perl, XPM or XPM2
 au BufNewFile,BufRead *.pm
@@ -1223,7 +1221,6 @@ au BufNewFile,BufRead *.pm
 
 " Perl POD
 au BufNewFile,BufRead *.pod			setf pod
-au BufNewFile,BufRead *.pod6			setf pod6
 
 " Php, php3, php4, etc.
 " Also Phtml (was used for PHP 2 in the past)
@@ -1366,6 +1363,9 @@ au BufNewFile,BufRead *.ptl,*.pyi,SConstruct		   setf python
 " Radiance
 au BufNewFile,BufRead *.rad,*.mat		setf radiance
 
+" Raku (formelly Perl6)
+au BufNewFile,BufRead *.pm6,*.p6,*.t6,*.pod6,*.raku,*.rakumod,*.rakudoc,*.rakutest  setf raku
+
 " Ratpoison config/command files
 au BufNewFile,BufRead .ratpoisonrc,ratpoisonrc	setf ratpoison
 

src/testdir/test_filetype.vim

@@ -359,7 +359,6 @@ let s:filename_checks = {
     \ 'pccts': ['file.g'],
     \ 'pdf': ['file.pdf'],
     \ 'perl': ['file.plx', 'file.al', 'file.psgi', 'gitolite.rc', '.gitolite.rc', 'example.gitolite.rc'],
-    \ 'perl6': ['file.p6', 'file.pm6', 'file.pl6', 'file.raku', 'file.rakumod'],
     \ 'pf': ['pf.conf'],
     \ 'pfmain': ['main.cf'],
     \ 'php': ['file.php', 'file.php9', 'file.phtml', 'file.ctp'],
@@ -375,7 +374,6 @@ let s:filename_checks = {
     \ 'plsql': ['file.pls', 'file.plsql'],
     \ 'po': ['file.po', 'file.pot'],
     \ 'pod': ['file.pod'],
-    \ 'pod6': ['file.pod6'],
     \ 'poke': ['file.pk'],
     \ 'postscr': ['file.ps', 'file.pfa', 'file.afm', 'file.eps', 'file.epsf', 'file.epsi', 'file.ai'],
     \ 'pov': ['file.pov'],
@@ -398,6 +396,7 @@ let s:filename_checks = {
     \ 'python': ['file.py', 'file.pyw', '.pythonstartup', '.pythonrc', 'file.ptl', 'file.pyi', 'SConstruct'],
     \ 'quake': ['anybaseq2/file.cfg', 'anyid1/file.cfg', 'quake3/file.cfg', 'baseq2/file.cfg', 'id1/file.cfg', 'quake1/file.cfg', 'some-baseq2/file.cfg', 'some-id1/file.cfg', 'some-quake1/file.cfg'],
     \ 'radiance': ['file.rad', 'file.mat'],
+    \ 'raku': ['file.pm6', 'file.p6', 'file.t6', 'file.pod6', 'file.raku', 'file.rakumod', 'file.rakudoc', 'file.rakutest'],
     \ 'ratpoison': ['.ratpoisonrc', 'ratpoisonrc'],
     \ 'rbs': ['file.rbs'],
     \ 'rc': ['file.rc', 'file.rch'],
@@ -624,7 +623,7 @@ let s:script_checks = {
       \          ['#!/path/pike0'],
       \          ['#!/path/pike9']],
       \ 'lua': [['#!/path/lua']],
-      \ 'perl6': [['#!/path/perl6']],
+      \ 'raku': [['#!/path/raku']],
       \ 'perl': [['#!/path/perl']],
       \ 'php': [['#!/path/php']],
       \ 'python': [['#!/path/python'],

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2788,
 /**/
     2787,
 /**/