Spreadsheet: Fix bug in content and alias lineedits

The two line edit widgets above the spreadsheet, one for exiting the
cell contents and one for editing the alias, were set to use the same
editing widget as the individual spreadsheet cells. Once that widget was
refactored to handle tab/enter behavior it was no longer the correct
widget for those elements. This commit changes them to
Gui::ExpressionLineEdit widgets instead, so that the Enter key works
correctly for them again.

src/Mod/Spreadsheet/Gui/Sheet.ui

@@ -27,7 +27,7 @@
       </widget>
      </item>
      <item row="0" column="1">
-      <widget class="SpreadsheetGui::LineEdit" name="cellContent">
+      <widget class="Gui::ExpressionLineEdit" name="cellContent">
        <property name="enabled">
         <bool>false</bool>
        </property>
@@ -44,7 +44,7 @@
       </widget>
      </item>
      <item row="0" column="3">
-      <widget class="SpreadsheetGui::LineEdit" name="cellAlias">
+      <widget class="Gui::ExpressionLineEdit" name="cellAlias">
        <property name="enabled">
         <bool>false</bool>
        </property>
@@ -68,9 +68,9 @@ Spreadsheet.my_alias_name instead of Spreadsheet.B1</string>
    <header>SheetTableView.h</header>
   </customwidget>
   <customwidget>
-   <class>SpreadsheetGui::LineEdit</class>
+   <class>Gui::ExpressionLineEdit</class>
    <extends>QLineEdit</extends>
-   <header>SpreadsheetView.h</header>
+   <header location="global">Gui/ExpressionCompleter.h</header>
   </customwidget>
  </customwidgets>
  <tabstops>

src/Mod/Spreadsheet/Gui/SpreadsheetView.cpp

@@ -99,10 +99,8 @@ SheetView::SheetView(Gui::Document *pcDocument, App::DocumentObject *docObj, QWi
             this, SLOT(rowResized(int, int, int)));
 
     connect(delegate, &SpreadsheetDelegate::finishedWithKey, this, &SheetView::editingFinishedWithKey);
-    connect(ui->cellContent, &LineEdit::finishedWithKey, this, [this](int, Qt::KeyboardModifiers) {confirmContentChanged(ui->cellContent->text()); });
-    connect(ui->cellContent, &LineEdit::returnPressed, this, [this]() {confirmContentChanged(ui->cellContent->text()); });
-    connect(ui->cellAlias, &LineEdit::finishedWithKey, this, [this](int, Qt::KeyboardModifiers) {confirmAliasChanged(ui->cellAlias->text()); });
-    connect(ui->cellAlias, &LineEdit::returnPressed, this, [this]() {confirmAliasChanged(ui->cellAlias->text()); });
+    connect(ui->cellContent, &ExpressionLineEdit::returnPressed, this, [this]() {confirmContentChanged(ui->cellContent->text()); });
+    connect(ui->cellAlias, &ExpressionLineEdit::returnPressed, this, [this]() {confirmAliasChanged(ui->cellAlias->text()); });
     connect(ui->cellAlias, &LineEdit::textEdited, this, &SheetView::aliasChanged);
 
     columnWidthChangedConnection = sheet->columnWidthChanged.connect(bind(&SheetView::resizeColumn, this, bp::_1, bp::_2));