search: prefer Iterable over List in some public APIs

lib/search/filter_kanji.dart

@@ -6,7 +6,7 @@ import 'package:sqflite_common/sqflite.dart';
 /// If [deduplicate] is true, the returned list will deduplicate the input kanji list before returning the filtered results.
 Future<List<String>> filterKanjiWithDbConnection(
   DatabaseExecutor connection,
-  List<String> kanji,
+  Iterable<String> kanji,
   bool deduplicate,
 ) async {
   final Set<String> filteredKanji = await connection
@@ -14,7 +14,7 @@ Future<List<String>> filterKanjiWithDbConnection(
       SELECT "literal"
       FROM "${KANJIDICTableNames.character}"
       WHERE "literal" IN (${kanji.map((_) => '?').join(',')})
-    ''', kanji)
+    ''', kanji.toList())
       .then((value) => value.map((e) => e['literal'] as String).toSet());
 
   if (deduplicate) {

lib/search/kanji_search.dart

@@ -274,7 +274,7 @@ Future<KanjiSearchResult?> searchKanjiWithDbConnection(
 /// Searches for multiple kanji at once, returning a map of kanji to their search results.
 Future<Map<String, KanjiSearchResult>> searchManyKanjiWithDbConnection(
   DatabaseExecutor connection,
-  Set<String> kanji,
+  Iterable<String> kanji,
 ) async {
   if (kanji.isEmpty) {
     return {};