Prefer const constructors in immutables (#117)

analysis_options.yaml

@@ -11,3 +11,4 @@ linter:
     - avoid_print
     - avoid_redundant_argument_values
     - prefer_const_constructors
+    - prefer_const_constructors_in_immutables

lib/widgets/default_styles.dart

@@ -5,7 +5,7 @@ import 'package:tuple/tuple.dart';
 class QuillStyles extends InheritedWidget {
   final DefaultStyles data;
 
-  QuillStyles({
+  const QuillStyles({
     required this.data,
     required Widget child,
     Key? key,

lib/widgets/editor.dart

@@ -169,7 +169,7 @@ class QuillEditor extends StatefulWidget {
   final ValueChanged<String>? onLaunchUrl;
   final EmbedBuilder embedBuilder;
 
-  QuillEditor(
+  const QuillEditor(
       {required this.controller,
       required this.focusNode,
       required this.scrollController,

lib/widgets/proxy.dart

@@ -7,7 +7,7 @@ class BaselineProxy extends SingleChildRenderObjectWidget {
   final TextStyle? textStyle;
   final EdgeInsets? padding;
 
-  BaselineProxy({Key? key, Widget? child, this.textStyle, this.padding})
+  const BaselineProxy({Key? key, Widget? child, this.textStyle, this.padding})
       : super(key: key, child: child);
 
   @override
@@ -73,7 +73,7 @@ class RenderBaselineProxy extends RenderProxyBox {
 }
 
 class EmbedProxy extends SingleChildRenderObjectWidget {
-  EmbedProxy(Widget child) : super(child: child);
+  const EmbedProxy(Widget child) : super(child: child);
 
   @override
   RenderEmbedProxy createRenderObject(BuildContext context) =>
@@ -145,7 +145,7 @@ class RichTextProxy extends SingleChildRenderObjectWidget {
         textHeightBehavior);
   }
 
-  RichTextProxy(
+  const RichTextProxy(
       RichText child,
       this.textStyle,
       this.textAlign,

lib/widgets/raw_editor.dart

@@ -55,7 +55,7 @@ class RawEditor extends StatefulWidget {
   final ScrollPhysics? scrollPhysics;
   final EmbedBuilder embedBuilder;
 
-  RawEditor(
+  const RawEditor(
       Key key,
       this.controller,
       this.focusNode,

lib/widgets/text_block.dart

@@ -61,7 +61,7 @@ class EditableTextBlock extends StatelessWidget {
   final CursorCont cursorCont;
   final Map<int, int> indentLevelCounts;
 
-  EditableTextBlock(
+  const EditableTextBlock(
       this.block,
       this.textDirection,
       this.verticalSpacing,

lib/widgets/text_line.dart

@@ -206,7 +206,7 @@ class EditableTextLine extends RenderObjectWidget {
   final double devicePixelRatio;
   final CursorCont cursorCont;
 
-  EditableTextLine(
+  const EditableTextLine(
       this.line,
       this.leading,
       this.body,

lib/widgets/toolbar.dart

@@ -182,7 +182,7 @@ class ToggleStyleButton extends StatefulWidget {
 
   final ToggleStyleButtonBuilder childBuilder;
 
-  ToggleStyleButton({
+  const ToggleStyleButton({
     required this.attribute,
     required this.icon,
     required this.controller,
@@ -266,7 +266,7 @@ class ToggleCheckListButton extends StatefulWidget {
 
   final Attribute attribute;
 
-  ToggleCheckListButton({
+  const ToggleCheckListButton({
     required this.icon,
     required this.controller,
     required this.attribute,
@@ -494,7 +494,7 @@ class ImageButton extends StatefulWidget {
 
   final ImageSource imageSource;
 
-  ImageButton({
+  const ImageButton({
     required this.icon,
     required this.controller,
     required this.imageSource,
@@ -600,7 +600,7 @@ class ColorButton extends StatefulWidget {
   final bool background;
   final QuillController controller;
 
-  ColorButton({
+  const ColorButton({
     required this.icon,
     required this.controller,
     required this.background,
@@ -738,7 +738,7 @@ class HistoryButton extends StatefulWidget {
   final bool undo;
   final QuillController controller;
 
-  HistoryButton({
+  const HistoryButton({
     required this.icon,
     required this.controller,
     required this.undo,
@@ -810,7 +810,7 @@ class IndentButton extends StatefulWidget {
   final QuillController controller;
   final bool isIncrease;
 
-  IndentButton({
+  const IndentButton({
     required this.icon,
     required this.controller,
     required this.isIncrease,
@@ -865,7 +865,8 @@ class ClearFormatButton extends StatefulWidget {
 
   final QuillController controller;
 
-  ClearFormatButton({required this.icon, required this.controller, Key? key})
+  const ClearFormatButton(
+      {required this.icon, required this.controller, Key? key,})
       : super(key: key);
 
   @override