patch 8.2.0270: some code not covered by tests

Problem:    Some code not covered by tests.
Solution:   Add test cases. (Yegappan Lakshmanan, closes #5649)
diff --git a/src/testdir/test_ex_mode.vim b/src/testdir/test_ex_mode.vim
index 7861477..bf10104 100644
--- a/src/testdir/test_ex_mode.vim
+++ b/src/testdir/test_ex_mode.vim
@@ -55,7 +55,7 @@
   let &encoding = encoding_save
 endfunc
 
-" Test subsittute confirmation prompt :%s/pat/str/c in Ex mode
+" Test substitute confirmation prompt :%s/pat/str/c in Ex mode
 func Test_Ex_substitute()
   CheckRunVimInTerminal
   let buf = RunVimInTerminal('', {'rows': 6})
@@ -77,6 +77,11 @@
   call term_sendkeys(buf, "q\<CR>")
   call WaitForAssert({-> assert_match(':', term_getline(buf, 6))}, 1000)
 
+  " Pressing enter in ex mode should print the current line
+  call term_sendkeys(buf, "\<CR>")
+  call WaitForAssert({-> assert_match('  3 foo foo',
+        \ term_getline(buf, 5))}, 1000)
+
   call term_sendkeys(buf, ":vi\<CR>")
   call WaitForAssert({-> assert_match('foo bar', term_getline(buf, 1))}, 1000)