(doc) improve formatting

Author: pniederlag

docs/usage/command-line.md

@@ -2,7 +2,7 @@
 
 If you want a command line version installed on your machine then you can use [Chocolatey](http://chocolatey.org) or [Homebrew](https://brew.sh/) to install GitVersion.
 
-> **Hint**: While documentation and help use '/' as command prefix the hyphen '-' is supported as well and is a better alternative for using on *nix system. Example: -output json vs. /output json
+> **Hint**: While documentation and help use '/' as command prefix the hyphen '-' is supported as well and is a better alternative for usage on \*nix systems. Example: *-output json vs. /output json*
 
 ## Chocolatey