As the title says, I would like to build a VS extension that's able to react to certain changes made on the editor window (for various languages). Not necessarily an adornment.
To do this I would like to be able to analyse the editor document through the Roslyn service API (that if I understood well is now part for the Microsoft.CodeAnalysis).
Can someone indicate some documentation? What's the best practice to do this?
What are the interface to import via MEF?
As example you can export a custom ISuggestedActionsSourceProvider to add new feature in the light bulb, you can use ExportCodeRefactoringProviderAttribute to add a new refactoring, also you can export IClassifierProvider and ITagProvider to classificate a elements in the text editor, import ITextDocumentFactoryService to retrieve the current VS Document by ITextBuffer and etc.
Also you wouldn't be enough to use only Microsoft.CodeAnalysis for some kind of analyzing, so you will need to add a some additional packages in these cases. As example these packages can be Microsoft.CodeAnalysis.EditorFeatures.Text, Microsoft.CodeAnalysis.Workspaces.Common and etc.
If you want to get from community the more concrete answer you should concrete what exactly do you want in the question.
Also you can check a more useful links and examples: Roslynator are refactoring and analyzing a code, Getting start editor extensions, Light bulb guide, Classification elements for highlighting