Press 'h'/'?' to get troubleshooting information

We should offer support for troubleshooting most common issues with using Dev Proxy:

- no requests intercepted
- requests intercepted but passed through
- SSL error in the app when using proxy

Users should be able to invoke this information by pressing 'h' or '?' (which one is more intuitive?).

Questions to decide:

- which hotkey to use
- should the information be available in the terminal or as a link that points to our docs

No files, tests, or implementation entry points are named. First resolve whether h or ? should invoke the help, and whether troubleshooting information belongs in the terminal or docs; done means the chosen shortcut presents guidance for all three listed proxy problems.

Written by the indexing model from the issue text.