patch 9.0.1804: Vim9: no support for private object methods

Problem:  Vim9: no support for private object methods
Solution: Add support for private object/class methods

closes: #12920

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>
diff --git a/src/structs.h b/src/structs.h
index ba712c1..b655e55 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -1489,8 +1489,8 @@
 #define TTFLAG_SUPER	    0x40    // object from "super".
 
 typedef enum {
-    VIM_ACCESS_PRIVATE,	// read/write only inside th class
-    VIM_ACCESS_READ,	// read everywhere, write only inside th class
+    VIM_ACCESS_PRIVATE,	// read/write only inside the class
+    VIM_ACCESS_READ,	// read everywhere, write only inside the class
     VIM_ACCESS_ALL	// read/write everywhere
 } omacc_T;
 
@@ -1790,6 +1790,7 @@
 
     class_T	*uf_class;	// for object method and constructor; does not
 				// count for class_refcount
+    int		uf_private;	// TRUE if class or object private method
 
     garray_T	uf_args;	// arguments, including optional arguments
     garray_T	uf_def_args;	// default argument expressions