patch 9.1.0220: Few typos in source and test files

Problem:  Typos in code and tests.
Solution: Fix typos (zeertzjq).

closes: #14321

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_recover.vim b/src/testdir/test_recover.vim
index a084ef4..e85b2e9 100644
--- a/src/testdir/test_recover.vim
+++ b/src/testdir/test_recover.vim
@@ -380,7 +380,7 @@
   call delete('Xfile1')
 endfunc
 
-" Test for :recover using a unreadable swap file
+" Test for :recover using an unreadable swap file
 func Test_recover_unreadable_swap_file()
   CheckUnix
   CheckNotRoot