patch 8.1.1068: cannot get all the information about current completion

Problem:    Cannot get all the information about current completion.
Solution:   Add complete_info(). (Shougo, Hirohito Higashi, closes #4106)
diff --git a/src/evalfunc.c b/src/evalfunc.c
index c1a32f3..6aff499 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -113,6 +113,7 @@
 static void f_complete(typval_T *argvars, typval_T *rettv);
 static void f_complete_add(typval_T *argvars, typval_T *rettv);
 static void f_complete_check(typval_T *argvars, typval_T *rettv);
+static void f_complete_info(typval_T *argvars, typval_T *rettv);
 #endif
 static void f_confirm(typval_T *argvars, typval_T *rettv);
 static void f_copy(typval_T *argvars, typval_T *rettv);
@@ -593,6 +594,7 @@
     {"complete",	2, 2, f_complete},
     {"complete_add",	1, 1, f_complete_add},
     {"complete_check",	0, 0, f_complete_check},
+    {"complete_info",	0, 1, f_complete_info},
 #endif
     {"confirm",		1, 4, f_confirm},
     {"copy",		1, 1, f_copy},
@@ -2600,6 +2602,29 @@
     rettv->vval.v_number = compl_interrupted;
     RedrawingDisabled = saved;
 }
+
+/*
+ * "complete_info()" function
+ */
+    static void
+f_complete_info(typval_T *argvars, typval_T *rettv)
+{
+    list_T	*what_list = NULL;
+
+    if (rettv_dict_alloc(rettv) != OK)
+	return;
+
+    if (argvars[0].v_type != VAR_UNKNOWN)
+    {
+	if (argvars[0].v_type != VAR_LIST)
+	{
+	    emsg(_(e_listreq));
+	    return;
+	}
+	what_list = argvars[0].vval.v_list;
+    }
+    get_complete_info(what_list, rettv->vval.v_dict);
+}
 #endif
 
 /*