Change wording, add 'Known Issues' section

Re-order distros to be alphabetical
Mention editing the script itself for configuration

README.md

@@ -1,19 +1,19 @@
 <div align="center">
 <h1>fet.sh</h1>
-fetch written in POSIX shell with no external commands
+a fetch written in POSIX shell with no external commands
 <br>
 <img src="screenshot.png" width="250px">
 </div>
 
 ### Installing
-**Arch:** [fet.sh-git](https://aur.archlinux.org/packages/fet.sh-git/) (AUR)  
-**Nix:** [fet-sh](https://search.nixos.org/packages?show=fet-sh&query=fet-sh&channel=unstable) (nixpkgs-unstable)  
+**Arch:** [fet.sh-git](https://aur.archlinux.org/packages/fet.sh-git) (AUR)  
 **Gentoo:** [app-misc/fetsh](https://gpo.zugaina.org/Overlays/guru/app-misc/fetsh) (GURU overlay)  
 **KISS:** [fetsh](https://github.com/kisslinux/community/tree/master/community/fetsh) (Community)  
-**Other Distros:** copy `fet.sh` to somewhere in $PATH
+**Nix:** [fet-sh](https://search.nixos.org/packages?show=fet-sh&query=fet-sh&channel=unstable) (nixpkgs-unstable)  
+Alternatively, copy `fet.sh` to somewhere in $PATH and mark it as executable (`chmod +x fet.sh`)
 
 ### Customization
-`fet.sh` can be configured using environment variables, for example:
+`fet.sh` has a few basic configuration options using environment variables, for example:
 ```
 $ info='n os wm sh n' fet.sh
 ```
@@ -21,3 +21,8 @@ Supported options are:
 - `accent` (0-7)
 - `info`
 - `separator`
+
+For less simple configuration I recommend editing the script, I tried to keep it simple.
+
+### Known Issues
+MacOS, BSD, and Android don't show much info.