#3390: rename hide_parse_errors to show_parse_errors

[llesha]

Fix of 3390 issue, changed hide_parse_errors to show_parse_errors

[ytmimi]

Thanks for your first contribution to rustfmt 🎉

There was a similar PR to rename fn_args_layout to fn_params_layout and deprecate fn_args_layout (#5387). Let's take a similar approach with this PR and create a set_hide_parse_errors function that encapsulate the logic of issuing a deprecation warning and setting show_parse_errors if it wasn't otherwise set.

Additionally, let's add hide_parse_errors to the HIDE_OPTIONS list (defined in is_hidden_option) to prevent hide_parse_errors from showing up in the output when a user tries to print their config with

rustfmt --print-config default

[ytmimi]

hide_parse_errors was an unstable option. The renamed option also needs to be marked as unstable.

[llesha]

What tracing issue should be mentioned? The same as the unstable option (#3390)? Unstable option's issue is about renaming it, so logically that issue is resolved in this PR.

[ytmimi]

Feel free to create a new tracking issue (I can add the unstable opiton label). We can also leave the tracking issue blank for now and follow up with it in a future PR. Up to you!

[llesha]

created issue #5977

[ytmimi]

@llesha we try to avoid merge commits in this repo. Can you please squash all these changes into a single commit and then rebase on the current master.

[ytmimi]

Thanks again for your first contribution to rustfmt and for helping to improve the clarity of rustfmt's configuration options!