Feat: added spellchecker service

lib/src/editor/spellchecker/default_spellchecker_service.dart

@@ -0,0 +1,11 @@
+import 'package:flutter/services.dart';
+import 'spellchecker_service.dart';
+
+class DefaultSpellcheckerService extends SpellcheckerService{
+  DefaultSpellcheckerService() : super(language: 'en');
+
+  @override
+  List<SuggestionSpan>? getSuggestions(String text) {
+    return null;
+  }
+}

lib/src/editor/spellchecker/spellchecker_service.dart

@@ -0,0 +1,12 @@
+import 'package:flutter/services.dart';
+
+abstract class SpellcheckerService {
+  SpellcheckerService({
+    required this.language,
+  });
+
+  final String language;
+  List<SuggestionSpan>? getSuggestions(String text);
+}
+
+

lib/src/editor/spellchecker/spellchecker_service_provider.dart

@@ -0,0 +1,19 @@
+import 'package:flutter/foundation.dart' show immutable;
+import 'default_spellchecker_service.dart';
+import 'spellchecker_service.dart';
+
+@immutable
+class SpellcheckerServiceProvider {
+  const SpellcheckerServiceProvider._();
+  static SpellcheckerService _instance = DefaultSpellcheckerService();
+
+  static SpellcheckerService get instance => _instance;
+
+  static void setInstance(SpellcheckerService service) {
+    _instance = service;
+  }
+
+  static void setInstanceToDefault() {
+    _instance = DefaultSpellcheckerService();
+  }
+}