patch 9.1.0840: filetype: idris2 files are not recognized

Problem:  filetype: idris2 files are not recognized
Solution: detect '*.idr' files as idris2, '*.lidr' files as lidris2
          and '*.ipkg' files as ipkg filetype (Serhii Khoma)

closes: #15987

Signed-off-by: Serhii Khoma <srghma@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_filetype.vim b/src/testdir/test_filetype.vim
index 9ddab96..cca619b 100644
--- a/src/testdir/test_filetype.vim
+++ b/src/testdir/test_filetype.vim
@@ -359,12 +359,14 @@
     ibasic: ['file.iba', 'file.ibi'],
     icemenu: ['/.icewm/menu', 'any/.icewm/menu'],
     icon: ['file.icn'],
+    idris2: ['file.idr'],
     indent: ['.indent.pro', 'indentrc'],
     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'],
+    ipkg: ['file.ipkg'],
     iss: ['file.iss'],
     ist: ['file.ist', 'file.mst'],
     j: ['file.ijs'],
@@ -415,6 +417,7 @@
     lftp: ['lftp.conf', '.lftprc', 'anylftp/rc', 'lftp/rc', 'some-lftp/rc'],
     lhaskell: ['file.lhs'],
     libao: ['/etc/libao.conf', '/.libao', 'any/.libao', 'any/etc/libao.conf'],
+    lidris2: ['file.lidr'],
     lifelines: ['file.ll'],
     lilo: ['lilo.conf', 'lilo.conf-file'],
     lilypond: ['file.ly', 'file.ily'],
diff --git a/src/version.c b/src/version.c
index f13567f..d00d280 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    840,
+/**/
     839,
 /**/
     838,