patch 8.1.1875: cannot get size and position of the popup menu

Problem:    Cannot get size and position of the popup menu.
Solution:   Add pum_getpos(). (Ben Jackson, closes #4827)
diff --git a/src/version.c b/src/version.c
index 8753421..2c02209 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1875,
+/**/
     1874,
 /**/
     1873,