A tag was recently created for autofac, which is an IoC container. The question that created this tag is also correctly tagged with dependency-injection.
A long, long time ago I wanted to create a tag for ninject (another IoC container) but I didn't have enough rep back then, and dependency-injection was deemed to encompass it properly. Turns out ninject was also created recently, on another Ninject-specific question.
While the specific IoC container chosen by the OP has zero importance as far as the application code is concerned (if DI is implemented correctly that is), the shape and content of an application's composition root (where the dependencies are resolved and the constructors are called and injected with the IoC-container-provided instances) and of its infrastructure code, is highly specific to the selected IoC container.
Therefore, I believe dependency-injection is not sufficient to properly tag a DI question that features code that is specific to an IoC container, and reviewers familiar with DI but only with certain containers might want to review autofac questions but skip or ignore ninject questions.
Is there a consensus that IoC container tags should be allowed to exist, or we should edit them out and simply use dependency-injection?