patch 9.1.0839: filetype: leo files are not recognized

Problem:  filetype: leo files are not recognized
Solution: detect '*.leo' files as leo filetype, include
          a filetype plugin (Riley Bruins)

References:
https://github.com/ProvableHQ/leo

closes: #15988

Signed-off-by: Riley Bruins <ribru17@hotmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_filetype.vim b/src/testdir/test_filetype.vim
index 050ff5f..9ddab96 100644
--- a/src/testdir/test_filetype.vim
+++ b/src/testdir/test_filetype.vim
@@ -408,6 +408,7 @@
     ldif: ['file.ldif'],
     lean: ['file.lean'],
     ledger: ['file.ldg', 'file.ledger', 'file.journal'],
+    leo: ['file.leo'],
     less: ['file.less'],
     lex: ['file.lex', 'file.l', 'file.lxx', 'file.l++'],
     lf: ['lfrc'],
diff --git a/src/version.c b/src/version.c
index d213e66..f13567f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    839,
+/**/
     838,
 /**/
     837,