Avoid redundant argument values (#114 An error occurred )

If it's ok, I would spend the day enabling linter rules so that the
codebase is more compliant with [Effective Dart](https://dart.dev/guides/language/effective-dart)
and thus more readable for new developers.

analysis_options.yaml

@@ -8,3 +8,4 @@ analyzer:
 linter:
   rules:
     - avoid_print
+    - avoid_redundant_argument_values

example/lib/pages/home_page.dart

@@ -110,7 +110,6 @@ class _HomePageState extends State<HomePage> {
                 autoFocus: false,
                 readOnly: false,
                 placeholder: 'Add content',
-                enableInteractiveSelection: true,
                 expands: false,
                 padding: EdgeInsets.zero,
                 customStyles: DefaultStyles(

example/lib/pages/read_only_page.dart

@@ -42,7 +42,6 @@ class _ReadOnlyPageState extends State<ReadOnlyPage> {
           focusNode: _focusNode,
           autoFocus: true,
           readOnly: !_edit,
-          enableInteractiveSelection: true,
           expands: false,
           padding: EdgeInsets.zero,
         ),

lib/models/documents/document.dart

@@ -183,7 +183,7 @@ class Document {
     bool nextOpIsImage =
         i + 1 < ops.length && ops[i + 1].isInsert && ops[i + 1].data is! String;
     if (nextOpIsImage && !(op.data as String).endsWith('\n')) {
-      res.push(Operation.insert('\n', null));
+      res.push(Operation.insert('\n'));
     }
     // Currently embed is equivalent to image and hence `is! String`
     bool opInsertImage = op.isInsert && op.data is! String;
@@ -193,7 +193,7 @@ class Document {
         (ops[i + 1].data as String).startsWith('\n');
     if (opInsertImage && (i + 1 == ops.length - 1 || !nextOpIsLineBreak)) {
       // automatically append '\n' for image
-      res.push(Operation.insert('\n', null));
+      res.push(Operation.insert('\n'));
     }
   }
 
@@ -213,7 +213,7 @@ class Document {
     _history.clear();
   }
 
-  String toPlainText() => _root.children.map((e) => e.toPlainText()).join('');
+  String toPlainText() => _root.children.map((e) => e.toPlainText()).join();
 
   void _loadDocument(Delta doc) {
     assert((doc.last.data as String).endsWith('\n'));

lib/models/quill_delta.dart

@@ -520,7 +520,7 @@ class Delta {
       if (op.isInsert) {
         inverted.delete(op.length!);
       } else if (op.isRetain && op.isPlain) {
-        inverted.retain(op.length!, null);
+        inverted.retain(op.length!);
         baseIndex += op.length!;
       } else if (op.isDelete || (op.isRetain && op.isNotPlain)) {
         final length = op.length!;

lib/widgets/controller.dart

@@ -31,7 +31,6 @@ class QuillController extends ChangeNotifier {
   TextEditingValue get plainTextEditingValue => TextEditingValue(
         text: document.toPlainText(),
         selection: selection,
-        composing: TextRange.empty,
       );
 
   Style getSelectionStyle() {

lib/widgets/editor.dart

@@ -200,7 +200,6 @@ class QuillEditor extends StatefulWidget {
         focusNode: FocusNode(),
         autoFocus: true,
         readOnly: readOnly,
-        enableInteractiveSelection: true,
         expands: false,
         padding: EdgeInsets.zero);
   }
@@ -726,8 +725,7 @@ class RenderEditor extends RenderEditableContainerBox
     );
     if (position.offset - word.start <= 1) {
       _handleSelectionChange(
-        TextSelection.collapsed(
-            offset: word.start, affinity: TextAffinity.downstream),
+        TextSelection.collapsed(offset: word.start),
         cause,
       );
     } else {

lib/widgets/raw_editor.dart

@@ -382,8 +382,6 @@ class RawEditorState extends EditorState
         TextInputConfiguration(
           inputType: TextInputType.multiline,
           readOnly: widget.readOnly,
-          obscureText: false,
-          autocorrect: true,
           inputAction: TextInputAction.newline,
           keyboardAppearance: widget.keyboardAppearance,
           textCapitalization: widget.textCapitalization,

lib/widgets/text_block.dart

@@ -623,7 +623,7 @@ class _NumberPoint extends StatelessWidget {
       n = (n / 26).floor();
     }
 
-    return result.toString().split('').reversed.join('');
+    return result.toString().split('').reversed.join();
   }
 
   String _intToRoman(int input) {

lib/widgets/toolbar.dart

@@ -525,7 +525,6 @@ class _ImageButtonState extends State<ImageButton> {
   Future<String?> _pickImageWeb() async {
     _paths = (await FilePicker.platform.pickFiles(
       type: _pickingType,
-      allowMultiple: false,
       allowedExtensions: (_extension?.isNotEmpty ?? false)
           ? _extension?.replaceAll(' ', '').split(',')
           : null,
@@ -1163,7 +1162,6 @@ class QuillIconButton extends StatelessWidget {
       child: RawMaterialButton(
         visualDensity: VisualDensity.compact,
         shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(2)),
-        padding: EdgeInsets.zero,
         fillColor: fillColor,
         elevation: 0,
         hoverElevation: hoverElevation,
@@ -1209,7 +1207,6 @@ class _QuillDropdownButtonState<T> extends State<QuillDropdownButton<T>> {
       child: RawMaterialButton(
         visualDensity: VisualDensity.compact,
         shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(2)),
-        padding: EdgeInsets.zero,
         fillColor: widget.fillColor,
         elevation: 0,
         hoverElevation: widget.hoverElevation,