patch 9.0.2167: Vim9: not consistently using :var for declarations

Problem:  Vim9-script object/class variable declarations use syntax
	  that is inconsistent with the rest of the language.
Solution: Use :var to declare object and class variables.

closes: #13670

Signed-off-by: Doug Kearns <dougkearns@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_vim9_disassemble.vim b/src/testdir/test_vim9_disassemble.vim
index 62da8c7..4e81122 100644
--- a/src/testdir/test_vim9_disassemble.vim
+++ b/src/testdir/test_vim9_disassemble.vim
@@ -3062,15 +3062,15 @@
   var lines =<< trim END
     vim9script
     interface I
-      this.o_var: number
-      this.o_var2: number
+      var o_var: number
+      var o_var2: number
     endinterface
 
     class C implements I
-      public static s_var: number
-      this.o_var: number
-      public static s_var2: number
-      this.o_var2: number
+      public static var s_var: number
+      var o_var: number
+      public static var s_var2: number
+      var o_var2: number
     endclass
 
     def F1(i: I)
@@ -3124,7 +3124,7 @@
     vim9script
 
     class A
-      public static val = 10
+      public static var val = 10
       def Foo(): number
         val = 20
         return val
@@ -3173,7 +3173,7 @@
   var lines =<< trim END
     vim9script
     class A
-      this.val: number = 10
+      var val: number = 10
     endclass
     g:instr = execute('disassemble A.new')
   END