patch 8.2.2956: Vim9: need to plan for future additions

Problem:    Vim9: need to plan for future additions.
Solution:   Reserve commands for future use: :type, :class, :enum.
diff --git a/src/ex_cmds.h b/src/ex_cmds.h
index aee2e6f..8a1ed5e 100644
--- a/src/ex_cmds.h
+++ b/src/ex_cmds.h
@@ -344,6 +344,9 @@
 EXCMD(CMD_clast,	"clast",	ex_cc,
 	EX_RANGE|EX_COUNT|EX_TRLBAR|EX_BANG,
 	ADDR_UNSIGNED),
+EXCMD(CMD_class,	"class",	ex_ni,
+	EX_EXTRA|EX_TRLBAR|EX_CMDWIN|EX_LOCK_OK,
+	ADDR_NONE),
 EXCMD(CMD_close,	"close",	ex_close,
 	EX_BANG|EX_RANGE|EX_COUNT|EX_TRLBAR|EX_CMDWIN|EX_LOCK_OK,
 	ADDR_WINDOWS),
@@ -548,9 +551,15 @@
 EXCMD(CMD_endif,	"endif",	ex_endif,
 	EX_TRLBAR|EX_SBOXOK|EX_CMDWIN|EX_LOCK_OK,
 	ADDR_NONE),
+EXCMD(CMD_endclass,	"endclass",	ex_ni,
+	EX_EXTRA|EX_TRLBAR|EX_CMDWIN|EX_LOCK_OK,
+	ADDR_NONE),
 EXCMD(CMD_enddef,	"enddef",	ex_endfunction,
 	EX_TRLBAR|EX_CMDWIN|EX_LOCK_OK,
 	ADDR_NONE),
+EXCMD(CMD_endenum,	"endenum",	ex_ni,
+	EX_EXTRA|EX_TRLBAR|EX_CMDWIN|EX_LOCK_OK,
+	ADDR_NONE),
 EXCMD(CMD_endfunction,	"endfunction",	ex_endfunction,
 	EX_TRLBAR|EX_CMDWIN|EX_LOCK_OK,
 	ADDR_NONE),
@@ -566,6 +575,9 @@
 EXCMD(CMD_enew,		"enew",		ex_edit,
 	EX_BANG|EX_TRLBAR,
 	ADDR_NONE),
+EXCMD(CMD_enum,		"enum",		ex_ni,
+	EX_EXTRA|EX_TRLBAR|EX_CMDWIN|EX_LOCK_OK,
+	ADDR_NONE),
 EXCMD(CMD_eval,		"eval",		ex_eval,
 	EX_EXTRA|EX_NOTRLCOM|EX_SBOXOK|EX_CMDWIN|EX_LOCK_OK,
 	ADDR_NONE),
@@ -1625,6 +1637,9 @@
 EXCMD(CMD_tunmap,	"tunmap",	ex_unmap,
 	EX_EXTRA|EX_TRLBAR|EX_NOTRLCOM|EX_CTRLV|EX_CMDWIN|EX_LOCK_OK,
 	ADDR_NONE),
+EXCMD(CMD_type,		"type",		ex_ni,
+	EX_EXTRA|EX_TRLBAR|EX_CMDWIN|EX_LOCK_OK,
+	ADDR_NONE),
 EXCMD(CMD_undo,		"undo",		ex_undo,
 	EX_RANGE|EX_COUNT|EX_ZEROR|EX_TRLBAR|EX_CMDWIN|EX_LOCK_OK,
 	ADDR_OTHER),