patch 8.1.2306: double and triple clicks are not tested

Problem:    Double and triple clicks are not tested.
Solution:   Test mouse clicks to select text. (closes #5226)
diff --git a/src/version.c b/src/version.c
index 8e2479e..dc6caed 100644
--- a/src/version.c
+++ b/src/version.c
@@ -742,6 +742,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2306,
+/**/
     2305,
 /**/
     2304,