New diagnostic to switch to DependencyPropertyGenerator

[HavenDV]

Hi. Your library is great and I use it in all WPF projects. I would like to ask about the possibility of providing a PR for you, which in Sileng/Suggestion mode would offer to switch to DependencyPropertyGenerator with automatic fix within the file/project/solution.
Although this generator is already in use in many projects, it may need to gain enough reputation for this, so this may be a proposal in the long run.