patch 8.1.2070: mouse code is spread out

Problem:    Mouse code is spread out.
Solution:   Move mouse terminal code parsing to mouse.c. (Yegappan Lakshmanan,
            closes #4966)
diff --git a/src/version.c b/src/version.c
index bfe483e..7f34d2a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -758,6 +758,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2070,
+/**/
     2069,
 /**/
     2068,