* add trailing commas on list/map/parameters

* add trailing commas on Invocation with nb of arg>1

* add commas for widget containing widgets

* add trailing commas if instantiation contains trailing comma

* revert bad change

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

It was causing problems rolling Flutter into Fuchsia

* re-enable lint unnecessary_const

* remove trailling whitespaces

* remove unnecessary const (after merge)

This reverts commit cc1cf13e.

Prevent header from thinking it can wrap and then overflowing.

Fix default footer string which lost its colon (localized values are fine).

Make the "rows per page" drop-down include at least one value even when the table lacks many items. (Previously it would assert if your table was too short.)

Make the footer scrollable.

Fix some todos and improve some debug output.

Tests for much of the above.

Aggressively apply the const lint.

This reverts commit ea21d0c5 which
didn't resolve the pagination control overflow issue. Commit
7425940d replaces this as an alternate
workaround. Once flutter/flutter#7980 is resolved, we should revert
7425940d and scroll instead.

The Ahem font has a much wider average text width than most fonts.

This yields a cleaner separation between common testing code
and actual tests (a distinction which is important in Google's
internal build system).

This patch adds a basic test for the DataTable widget.