vim-patch:9.1.0390: filetype: inko files are not recognized

Problem:  filetype: inko files are not recognized
Solution: Detect '*.inko' as ink filetype
          (Yorick Peterse)

See:
- https://github.com/inko-lang/inko.vim
- https://inko-lang.org/

closes: vim/vim#14699

a01968448a

Co-authored-by: Yorick Peterse <git@yorickpeterse.com>

runtime/lua/vim/filetype.lua

@@ -545,6 +545,7 @@ local extension = {
   inf = 'inform',
   INF = 'inform',
   ii = 'initng',
+  inko = 'inko',
   inp = detect.inp,
   ms = detect_seq(detect.nroff, 'xmath'),
   iss = 'iss',

test/old/testdir/test_filetype.vim

@@ -345,6 +345,7 @@ func s:GetFilenameChecks() abort
     \ 'inform': ['file.inf', 'file.INF'],
     \ 'initng': ['/etc/initng/any/file.i', 'file.ii', 'any/etc/initng/any/file.i'],
     \ 'inittab': ['inittab'],
+    \ 'inko': ['file.inko'],
     \ 'ipfilter': ['ipf.conf', 'ipf6.conf', 'ipf.rules'],
     \ 'iss': ['file.iss'],
     \ 'ist': ['file.ist', 'file.mst'],