patch 8.2.4112: function not deleted at end of test

Problem:    Function not deleted at end of test.
Solution:   Delete the function.
diff --git a/src/testdir/test_diffmode.vim b/src/testdir/test_diffmode.vim
index b10f96d..57115de 100644
--- a/src/testdir/test_diffmode.vim
+++ b/src/testdir/test_diffmode.vim
@@ -1212,7 +1212,9 @@
   call DiffMaintainsChangeMark()
   set diffopt+=internal
   call DiffMaintainsChangeMark()
+
   set diffopt&
+  delfunc DiffMaintainsChangeMark
 endfunc
 
 " Test for 'patchexpr'
diff --git a/src/version.c b/src/version.c
index ec1ba92..44691de 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4112,
+/**/
     4111,
 /**/
     4110,