Color scheme: Reduce minimum size and add scroll area to details

First thing that should happen when reducing the size of the preferences
dialog is to add a vertical scroll bar to the color scheme details, not
to the whole settings page.

Change-Id: Ifaa6d21627f26ec1a6426cdae2477f6143454c57
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/texteditor/colorschemeedit.cpp

@@ -152,6 +152,8 @@ ColorSchemeEdit::ColorSchemeEdit(QWidget *parent) :
 {
     setContentsMargins(0, layoutSpacing, 0, 0);
     m_ui->setupUi(this);
+    m_ui->detailsScrollArea->viewport()->setAutoFillBackground(false);
+    m_ui->scrollAreaWidgetContents->setAutoFillBackground(false);
     m_ui->itemList->setModel(m_formatsModel);
 
     populateUnderlineStyleComboBox();

src/plugins/texteditor/fontsettingspage.ui

@@ -6,7 +6,7 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>614</width>
+    <width>639</width>
     <height>306</height>
    </rect>
   </property>
@@ -173,7 +173,7 @@
       <item row="1" column="0" colspan="3">
        <widget class="TextEditor::Internal::ColorSchemeEdit" name="schemeEdit" native="true">
         <property name="sizePolicy">
-         <sizepolicy hsizetype="Preferred" vsizetype="MinimumExpanding">
+         <sizepolicy hsizetype="Preferred" vsizetype="Expanding">
           <horstretch>0</horstretch>
           <verstretch>1</verstretch>
          </sizepolicy>