patch 8.2.4892: test failures because of changed error messages

Problem:    Test failures because of changed error messages.
Solution:   Adjust the exptected error messages.
diff --git a/src/testdir/test_vimscript.vim b/src/testdir/test_vimscript.vim
index 619006f..c9f58c2 100644
--- a/src/testdir/test_vimscript.vim
+++ b/src/testdir/test_vimscript.vim
@@ -3077,7 +3077,7 @@
     endif
   END
   call writefile(code, 'Xtest')
-  call AssertException(['source Xtest'], 'Vim(else):E583: multiple :else')
+  call AssertException(['source Xtest'], 'Vim(else):E583: Multiple :else')
 
   " :elseif after :else
   let code =<< trim END