patch 9.0.1722: wrong error messages when passing wrong types to count()

Problem: wrong error messages when passing wrong types to count()
Solution: fix it

This fixes two problems:
1. When passing wrong type to {ic} argument of count(), two error
   messages are given, the second of which is misleading.
2. When passing wrong type to {comp} argument of count(), the error
   message doesn't mention that {comp} may be a String.

closes: #12825

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: zeertzjq <zeertzjq@outlook.com>
diff --git a/src/errors.h b/src/errors.h
index 6ef4700..1c1b146 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -1802,7 +1802,8 @@
 	INIT(= N_("E704: Funcref variable name must start with a capital: %s"));
 EXTERN char e_variable_name_conflicts_with_existing_function_str[]
 	INIT(= N_("E705: Variable name conflicts with existing function: %s"));
-// E706 unused
+EXTERN char e_argument_of_str_must_be_list_string_or_dictionary[]
+	INIT(= N_("E706: Argument of %s must be a List, String or Dictionary"));
 EXTERN char e_function_name_conflicts_with_variable_str[]
 	INIT(= N_("E707: Function name conflicts with variable: %s"));
 EXTERN char e_slice_must_come_last[]
diff --git a/src/list.c b/src/list.c
index d52c23d..933480f 100644
--- a/src/list.c
+++ b/src/list.c
@@ -2735,8 +2735,9 @@
 	else
 	    n = dict_count(argvars[0].vval.v_dict, &argvars[1], ic);
     }
-    else
-	semsg(_(e_argument_of_str_must_be_list_or_dictionary), "count()");
+    else if (!error)
+	semsg(_(e_argument_of_str_must_be_list_string_or_dictionary),
+								    "count()");
     rettv->vval.v_number = n;
 }
 
diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index 750c4a2..e5d56ac 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -1749,7 +1749,8 @@
   call assert_equal(2, count("fooooo", "oo"))
   call assert_equal(0, count("foo", ""))
 
-  call assert_fails('call count(0, 0)', 'E712:')
+  call assert_fails('call count(0, 0)', 'E706:')
+  call assert_fails('call count("", "", {})', ['E728:', 'E728:'])
 endfunc
 
 func Test_changenr()
diff --git a/src/version.c b/src/version.c
index c4098c2..1809d0d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1722,
+/**/
     1721,
 /**/
     1720,