patch 8.2.2860: adding a text property causes the whole window to be redawn

Problem:    Adding a text property causes the whole window to be redawn.
Solution:   Use changed_lines_buf() to only redraw the affected lines.
diff --git a/src/change.c b/src/change.c
index 50dc105..248e6d8 100644
--- a/src/change.c
+++ b/src/change.c
@@ -758,7 +758,7 @@
 /*
  * Marks the area to be redrawn after a change.
  */
-    static void
+    void
 changed_lines_buf(
     buf_T	*buf,
     linenr_T	lnum,	    // first line with change