This reverts commit 5fd259be.

This does a cleanup of the examples, removing all of the "section" markers and extra comments that we don't need anymore now that the samples are no longer in the source code. It also removes the --template arguments from the {@tool dartpad} and {@tool sample} directives, since those are no longer used. It converts two examples that I discovered were still embedded into linked examples in the examples folder.

I didn't delete the templates from the snippets config folder yet, because there are still embedded samples in the dart:ui package from the engine that use them. Once dart:ui no longer uses the templates, they can be removed.

I bumped the version of the snippets package to pick up a change that allows removal of the --template argument.

* Make sure Opacity widgets/layers do not drop the offset

This reverts commit 0d0f7a4f.

Simplifying and refactoring parts of RenderEditable. Functionality is the same.

Reland "Fixes listview shrinkwrap and hidden semantics node gets updated incorrectly. (#88814)" (#89184)

Keyboard shortcuts near wordwrapped lines could be buggy before this fix.

* Add missing parameters to DecorationImage

* tune docs

* fix test

This extracts the sample code out from the API doc comments, and places them in separate files on disk, allowing running of the examples locally, testing them, and building of slightly larger examples.

Revert "Fixes listview shrinkwrap and hidden semantics node gets updated incorrectly. (#88814)" (#88886)

This reverts commit 0e9665e4.

* Fixes renderparagraph crashes due to truncated semantics node

* add period

Consolidate duplicated cut/copy/paste/selectall code so it can be done via Actions in the future.

Revert "[EditableText] call `onSelectionChanged` only when there're actual selection/cause changes (#87971)" (#88183)