vim-patch:8.2.5019: cannot get the first screen column of a character (#23312)

Problem:    Cannot get the first screen column of a character.
Solution:   Let virtcol() optionally return a list. (closes vim/vim#10482,
            closes vim/vim#7964)

0f7a3e1de6

Co-authored-by: LemonBoy <thatlemon@gmail.com>

test/old/testdir/test_functions.vim

@@ -2607,4 +2607,15 @@ func Test_builtin_check()
 endfunc
 
 
+" Test for virtcol()
+func Test_virtcol()
+  enew!
+  call setline(1, "the\tquick\tbrown\tfox")
+  norm! 4|
+  call assert_equal(8, virtcol('.'))
+  call assert_equal(8, virtcol('.', v:false))
+  call assert_equal([4, 8], virtcol('.', v:true))
+  bwipe!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab