runtime(vim): Update base-syntax, match types in Vim9 variable declarations

Match types in Vim9 variable declarations.

Match Vim9 boolean and null literals. These are not matched in all
contexts yet.

related: #15277

Signed-off-by: Doug Kearns <dougkearns@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/syntax/testdir/input/vim_ex_commands.vim

@@ -98,7 +98,6 @@
 :checkpath
 :checktime
 :chistory
-:class
 :clast
 :clearjumps
 :clist
@@ -172,7 +171,6 @@
 :else
 :elseif
 :emenu
-:endclass
 :enddef
 :endif
 :endfor
@@ -184,7 +182,6 @@
 :ex
 :execute
 :exit
-:export
 :exusage
 :file
 :files
@@ -553,12 +550,10 @@
 :unsilent
 :update
 :vglobal/.../
-:var
 :version
 :verbose
 :vertical
 :vim9cmd
-" :vim9script
 :vimgrep
 :vimgrepadd
 :visual
@@ -691,7 +686,6 @@ call Foo() | chdir
 call Foo() | checkpath
 call Foo() | checktime
 call Foo() | chistory
-call Foo() | class
 call Foo() | clast
 call Foo() | clearjumps
 call Foo() | clist
@@ -765,7 +759,6 @@ call Foo() | echowindow
 call Foo() | else
 call Foo() | elseif
 call Foo() | emenu
-call Foo() | endclass
 call Foo() | enddef
 call Foo() | endif
 call Foo() | endfor
@@ -777,7 +770,6 @@ call Foo() | eval
 call Foo() | ex
 call Foo() | execute
 call Foo() | exit
-call Foo() | export
 call Foo() | exusage
 call Foo() | file
 call Foo() | files
@@ -1147,12 +1139,10 @@ call Foo() | unmenu
 call Foo() | unsilent
 call Foo() | update
 call Foo() | vglobal/.../
-call Foo() | var
 call Foo() | version
 call Foo() | verbose
 call Foo() | vertical
 call Foo() | vim9cmd
-" call Foo() | vim9script
 call Foo() | vimgrep
 call Foo() | vimgrepadd
 call Foo() | visual
@@ -1193,3 +1183,39 @@ call Foo() | xunmap
 call Foo() | xunmenu
 call Foo() | yank
 call Foo() | z
+
+
+" Vim9-script only
+
+:abstract
+:class
+:defcompile
+:disassemble
+:endclass
+:endinterface
+:endenum
+:enum
+:export
+:final
+:interface
+:public
+:static
+:type
+:var
+
+Foo() | abstract
+Foo() | class
+Foo() | defcompile
+Foo() | disassemble
+Foo() | endclass
+Foo() | endenum
+Foo() | endinterface
+Foo() | enum
+Foo() | export
+Foo() | final
+Foo() | interface
+Foo() | public
+Foo() | static
+Foo() | type
+Foo() | var
+