add net to status_right, solves #4

[HarHarLinks]

uses unicode point f6ff (nf-mdi-ethernet) as defined by nerdfonts

todo(?): variate icon to indicate whether ethernet or wireless is connected

[caiogondim]

Would that run on macOS?

[HarHarLinks]

In short: I think it wouldn't break on macOS, but be a useless waste of space.

(Just noting my thougths/to do:)

• regarding 558d591: tmux-net-speed does not support macOS (as stated by it's readme). Will fix so it's only enabled when supported.
• regarding 3108a9a: I have no experience with mac, and a quick google makes me think acpi is not available as it usually is on linux. Similar tools use pmset or ioreg on mac, however I don't feel comfortable with coding that blindly as I have no mac for testing. While chances are you would only install the plugin when you know your system has a battery, it's probably not a bad idea to keep this portable if you want to use your config on several machines. Will fix so check is ignored if it fails.
• it's probably a good idea to make the icon portable/configurable as f6ff seems rather specific in hindsight. Will look into that, as well as tmux-online-status.

[HarHarLinks]

Turns out, this is how it works later on in the battery function, so it is just as compatible.
While I believe this isn't perfect, it should work on linux as long as battery drivers work properly.

No Idea what happens on macOS without battery (iMac, Mac Pro) or how to handle it if necessary.