patch 8.2.1293: Vim9: error when using vim9script in TextYankPost

Problem:    Vim9: error when using vim9script in TextYankPost.
Solution:   Use EX_LOCKOK instead of the EX_CMDWIN flag for command that can
            be used when text is locked. (closes #6529)
diff --git a/src/vim9compile.c b/src/vim9compile.c
index 53bfb6c..746c9aa 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -3755,7 +3755,9 @@
 	    }
 	}
 
-	if (*p == '(')
+	// Do not skip over white space to find the "(", "exeucte 'x' ()" is
+	// not a function call.
+	if (**arg == '(')
 	{
 	    garray_T    *stack = &cctx->ctx_type_stack;
 	    type_T	*type;