patch 8.1.1337: get empty text prop when splitting line just after text prop

Problem:    Get empty text prop when splitting line just after text prop.
Solution:   Do not create an empty text prop at the start of the line.

src/testdir/test_textprop.vim

@@ -316,16 +316,15 @@ func Test_prop_open_line()
   call assert_equal(expected, prop_list(2))
   call DeletePropTypes()
 
-  " split just after first prop, empty prop and second prop move to next line
+  " split just after first prop, second prop move to next line
   let expected = SetupOneLine() " 'xonex xtwoxx'
   exe "normal 0fea\<CR>\<Esc>"
   call assert_equal('xone', getline(1))
   call assert_equal('x xtwoxx', getline(2))
   let exp_first = expected[0:0]
   call assert_equal(exp_first, prop_list(1))
-  let expected[0].col = 1
-  let expected[0].length = 0
-  let expected[1].col -= 4
+  let expected = expected[1:1]
+  let expected[0].col -= 4
   call assert_equal(expected, prop_list(2))
   call DeletePropTypes()
 

src/textprop.c

@@ -1075,7 +1075,9 @@ adjust_props_for_split(
 	    ++prevprop.ga_len;
 	}
 
-	if (prop.tp_col + prop.tp_len >= skipped && ga_grow(&nextprop, 1) == OK)
+	// Only add the property to the next line if the length is bigger than
+	// zero.
+	if (prop.tp_col + prop.tp_len > skipped && ga_grow(&nextprop, 1) == OK)
 	{
 	    p = ((textprop_T *)nextprop.ga_data) + nextprop.ga_len;
 	    *p = prop;

src/version.c

@@ -767,6 +767,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1337,
 /**/
     1336,
 /**/