Updates which characters are allowed in the dataset name based on
external documentation, and removes restriction on not allowing the
name to start with `xml`. These restrictions are not enforced in the
name parsing in `_DataAttributeMap`. Note, there is an additional
restriction in our docs which is inconsistent with external behavior
disallowing capital letters.
Change-Id: I4143503b17673be2e038df8647fef7c9ac09e9ba
Bug: https://github.com/dart-lang/sdk/issues/43295
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/219180
Reviewed-by: Sigmund Cherem <sigmund@google.com>
Commit-Queue: Riley Porter <rileyporter@google.com>
Riley Porter
11dc2f4ff6