patch 8.1.1910: redrawing too much when toggling 'relativenumber'

Problem:    Redrawing too much when toggling 'relativenumber'.
Solution:   Only clear when 'signcolumn' is set to "number". (Yegappan
            Lakshmanan, closes #4852)
diff --git a/src/version.c b/src/version.c
index 37b0f79..98f368c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1910,
+/**/
     1909,
 /**/
     1908,