patch 8.2.1023: Vim9: redefining a function uses a new index every time

Problem:    Vim9: redefining a function uses a new index every time.
Solution:   When redefining a function clear the contents and re-use the
            index.
diff --git a/src/proto/vim9compile.pro b/src/proto/vim9compile.pro
index 41c6887..0db5fc7 100644
--- a/src/proto/vim9compile.pro
+++ b/src/proto/vim9compile.pro
@@ -14,6 +14,6 @@
 int compile_def_function(ufunc_T *ufunc, int set_return_type, cctx_T *outer_cctx);
 void set_function_type(ufunc_T *ufunc);
 void delete_instr(isn_T *isn);
-void delete_def_function(ufunc_T *ufunc);
+void clear_def_function(ufunc_T *ufunc);
 void free_def_functions(void);
 /* vim: set ft=c : */