DOC: Add TextFileReader to docs
- [x] closes #46187 (Replace xxxx with the Github issue number)
- [x] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).

@twoertwein Anything else you would want to add?

If it is a public class, it should also be possible to import it (for example, for typing purposes). Need to declare that `parsers` is public in `io/__init__.py` (`io/parsers/__init_.py` already limits the scope to not make everything in it public).

Need to import io.parsers here and add it to this list: https://github.com/pandas-dev/pandas/blob/471319ba78c540766368a7a5e784ab20424ba9e1/pandas/io/__init__.py#L12 This pull request is stale because it has been open for thirty days with no activity. Please [update](https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#updating-your-pull-request) and respond to this comment if you're still interested in working on this. @phofl do you still want to work on this? This pull request is stale because it has been open for thirty days with no activity. Please [update](https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#updating-your-pull-request) and respond to this comment if you're still interested in working on this. Still interested in this @phofl?  I should :) Would like to keep open for a bit longer @phofl went ahead and fixed the typo, let's see if CI is green, and I think we can get this merged. Seems like the doctests still don't pass because of the ellipsis, will have a look later. @phofl is this still active? Yeah we should probably fix this Looks like this has gone stale, feel free to reopen if/when you have time to circle back