Adding this via a properties object that encompasses all of the optional
properties. This way if we need to add more items that are optional we
can continue to do so without overload explosion.
- Renamed many of our `RazorSourceDocument` abstractions to not include the word `Razor`.
- Added a `GetChecksum()` method to `RazorSourceDocument` to allow source documents to compute their own checksums.
- Re-generated codegen tests that did not normalize new lines. Ones that did re-generate newlines converted from stream => string => normalized string and then ran the Razor parser.
- Added tests to validate `GetChecksum` for all source document types.
- Removed unused `LegacySourceDocument`.
Ryan Nowak
N. Taylor Mullen