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.
0d511a6dd2