patch 8.2.0775: not easy to call a Vim function from Lua

Problem:    Not easy to call a Vim function from Lua.
Solution:   Add vim.call() and vim.fn(). (Prabir Shrestha, closes #6063)
diff --git a/src/version.c b/src/version.c
index 9511379..cc092c2 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    775,
+/**/
     774,
 /**/
     773,