patch 9.0.2084: Vim9: abstract static methods are possible

Problem:  Vim9: abstract static methods are possible
Solution: Disallow abstract static methods

fixes: #13462
closes: #13466

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/vim9class.c b/src/vim9class.c
index 436b2a8..ede310b 100644
--- a/src/vim9class.c
+++ b/src/vim9class.c
@@ -1571,9 +1571,9 @@
 
 		abstract_method = TRUE;
 		p = skipwhite(pa + 8);
-		if (STRNCMP(p, "def", 3) != 0 && STRNCMP(p, "static", 6) != 0)
+		if (STRNCMP(p, "def", 3) != 0)
 		{
-		    emsg(_(e_abstract_must_be_followed_by_def_or_static));
+		    emsg(_(e_abstract_must_be_followed_by_def));
 		    break;
 		}
 	    }