patch 8.2.3871: list.c contains code for dict and blob

Problem:    List.c contains code for dict and blob.
Solution:   Refactor to put code where it belongs. (Yegappan Lakshmanan,
            closes #9386)
diff --git a/src/proto/list.pro b/src/proto/list.pro
index 97e6c47..5b7414b 100644
--- a/src/proto/list.pro
+++ b/src/proto/list.pro
@@ -50,6 +50,7 @@
 void f_list2str(typval_T *argvars, typval_T *rettv);
 void f_sort(typval_T *argvars, typval_T *rettv);
 void f_uniq(typval_T *argvars, typval_T *rettv);
+int filter_map_one(typval_T *tv, typval_T *expr, filtermap_T filtermap, typval_T *newtv, int *remp);
 void f_filter(typval_T *argvars, typval_T *rettv);
 void f_map(typval_T *argvars, typval_T *rettv);
 void f_mapnew(typval_T *argvars, typval_T *rettv);