Fix config edit mac os

[MikeBirdTech]

Describe the changes you have made:

Added the try...except in case MacOS does not have xdg-open installed and calls open instead. Previous functionality that was removed when updating config_file to config_directory as seen in 3241ae4#diff-dbfabffe97449287c29c05be833deaec361f15787ac3befc0ad745b826d9867bR301-R322

Reference any relevant issues (e.g. "Fixes #000"):

Pre-Submission Checklist (optional but appreciated):

• I have included relevant documentation updates (stored in /docs)
• I have read docs/CONTRIBUTING.md
• I have read docs/ROADMAP.md

OS Tests (optional but appreciated):

• Tested on Windows
• Tested on MacOS
• Tested on Linux

[KillianLucas]

Oh my god, I mistakenly committed that. Working on a new config system that lets you use multiple files. This is great, thanks!

Fantastic to have the Termux guide in there too! We should move that into a guide sections in the docs in the next couple days. Merging.