patch 9.0.1001: classes are not documented or implemented yet

Problem:    Classes are not documented or implemented yet.
Solution:   Make the first steps at documenting Vim9 objects, classes and
            interfaces.  Make initial choices for the syntax.  Add a skeleton
            implementation.  Add "public" and "this" in the command table.
diff --git a/src/Make_ami.mak b/src/Make_ami.mak
index a642d91..9e9ebe3 100644
--- a/src/Make_ami.mak
+++ b/src/Make_ami.mak
@@ -174,6 +174,7 @@
 	userfunc.c \
 	version.c \
 	viminfo.c \
+	vim9class.c \
 	vim9cmds.c \
 	vim9compile.c \
 	vim9execute.c \