It's not a bot but formatters like prettier for example make it very easy to set them up as git-hooks, where the formatter is applied on commit. Meaning, unless you specifically commit without hooks, all committed code should comply with the formatter.

For linting (e.g. eslint in the JS-space), this is also possible, however, most linting-processes tend to run just long enough to be annoying when run on every commit. In the monorepo I work on we created a command "prep-pr" which specifically addresses this issue - run it before creating a PR, and the CI-pipeline will mostly be green, at least in terms of linting/unit-testing.