Remove 1745 decorative breaks

Documentation improvements

Remove window reference from doc snippet

* Remove superfluous words from comments.

* Revert `win32_window.h`

Which seems to come from `gallery`

* Add Decoding Flutter videos to API docs

* Review comments

* Update widget of the week videos too

* Remove unnecessary null checks in flutter/foundation

* Remove unnecessary null checks in flutter/services

* Remove unnecessary null checks in flutter/physics

Use `curly_braces_in_flow_control_structures` for `foundation`, `gestures`, `painting`, `physics` (#104610)

* Use `curly_braces_in_flow_control_structures` for `foundation`

* Use `curly_braces_in_flow_control_structures` for `gestures`

* Use `curly_braces_in_flow_control_structures` for `painting`

* Use `curly_braces_in_flow_control_structures` for `physics`

* fix comments

* remove trailing space

* fix TODO style

* fix deprecated_new_in_comment_reference for `material` library

in a future version of the SDK, these will be flagged, fix them now

* Update pubspec.yaml

This reverts commit 5fd259be.

Update samples to use repo analysis options, Fix sample templates and a ton of analyzer issues (#77868)

* Migrate

* apply upcoming lint cast_nullable_to_non_nullable

* make RenderObjectElement.renderObject non-nullable

* Add punctuation for unterminated sentences in doc comments

* Addressing review nit