patch 8.1.2150: no test for 'ttymouse' set from xterm version response

Problem:    No test for 'ttymouse' set from xterm version response.
Solution:   Test the three possible values.
diff --git a/src/version.c b/src/version.c
index 3fc889e..a8dc708 100644
--- a/src/version.c
+++ b/src/version.c
@@ -754,6 +754,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2150,
+/**/
     2149,
 /**/
     2148,