patch 9.1.1922: Wrong virtcol('$') with virtual text at EOL

Problem:  Wrong virtcol('$') with virtual text at EOL (rickhowe).
Solution: Also add 1 to end virtcol when there is virtual text.
          (zeertzjq)

fixes: #18761
closes: #18762

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/charset.c

@@ -1702,8 +1702,7 @@ getvcol(
 	    {
 		incr = 1;	// NUL at end of line only takes one column
 #ifdef FEAT_PROP_POPUP
-		if (cts.cts_cur_text_width > 0)
-		    incr = cts.cts_cur_text_width;
+		incr += cts.cts_cur_text_width;
 		on_NUL = TRUE;
 #endif
 		break;

src/testdir/test_textprop.vim

@@ -4403,6 +4403,22 @@ func Test_text_eol_long_wrap_smoothscroll()
   call StopVimInTerminal(buf)
 endfunc
 
+func Test_text_eol_virtcol()
+  new
+  call prop_type_add('test', #{highlight: 'ErrorMsg'})
+  call setline(1, repeat(['1234567890'], 6))
+
+  for [ln, tx] in [[2, 'a'], [3, 'ab'], [4, 'abc'], [5, 'abcd'], [6, 'αβγ口']]
+    let co = col([ln, '$'])
+    call assert_equal(11, virtcol([ln, '$']))
+    call prop_add(ln, co, #{type: 'test', text: tx})
+    call assert_equal(11 + strwidth(tx), virtcol([ln, '$']))
+  endfor
+
+  bwipe!
+  call prop_type_delete('test')
+endfunc
+
 func Test_text_below_nowrap()
   CheckScreendump
   CheckRunVimInTerminal

src/version.c

@@ -729,6 +729,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1922,
 /**/
     1921,
 /**/