## Description
This checks API doc strings for malformed links to examples. It prevents errors in capitalization, spacing, number of asterisks, etc. It won't catch all errors, because it needs to have a minimally indicative string to know that it even is trying to be a link to an example. At a minimum, the line needs to look like (literally, not as a regexp) `///*seecode.*` in order to be seen as a link to an example.
Separately, I'm going to add a check to the snippets tool that checks to make sure that an `{@tool}` block includes either a link to a sample file or a dart code block.
## Tests
- Added a test to make sure it catches some malformed links.
Fixes#119401
This PR is to:
* add `Card.filled` and `Card.outlined` factory methods so that we can use tokens for these two types of cards to generate default theme instead of providing hard-corded values in example.
* update card.2.dart example.
* add test file for card.2.dart example.
* fix some mismatch caused by editing the auto-generated defaults by hand in navigation_bar.dart and navigation_drawer.dart.
