I do a git diff after every git status before adding/committing. Do IDEs show diff before committing? Jetbrains IDEs do show diff between subsequent commits. Although they do highlight which files have been modified.
Not as part of the same operation, but the usual workflow is that there's a pane in the somewhere that lists all modified and staged files, and you can click on those to see diffs (or just click "commit" if you don't care).
