patch 8.2.1714: text properties corrupted with substitute command

Problem:    Text properties corrupted with substitute command. (Filipe
            Brandenburger)
Solution:   Get the changed line again after using u_savesub(). (closes #6984)

Author: brammool

src/testdir/test_textprop.vim

@@ -1132,6 +1132,19 @@ func Test_proptype_substitute2()
   bwipe!
 endfunc
 
+" This was causing property corruption.
+func Test_proptype_substitute3()
+  new
+  call setline(1, ['abcxxx', 'def'])
+  call prop_type_add("test", {"highlight": "Search"})
+  call prop_add(1, 2, {"end_lnum": 2, "end_col": 2, "type": "test"})
+  %s/x\+$//
+  redraw
+
+  call prop_type_delete('test')
+  bwipe!
+endfunc
+
 func SaveOptions()
   let d = #{tabstop: &tabstop,
 	  \ softtabstop: &softtabstop,

src/textprop.c

@@ -1349,6 +1349,10 @@ adjust_prop_columns(
 						    && u_savesub(lnum) == FAIL)
 		return FALSE;
 	    dirty = TRUE;
+
+	    // u_savesub() may have updated curbuf->b_ml, fetch it again
+	    if (curbuf->b_ml.ml_line_lnum != lnum)
+		proplen = get_text_props(curbuf, lnum, &props, TRUE);
 	}
 	if (res.can_drop)
 	    continue; // Drop this text property

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1714,
 /**/
     1713,
 /**/