use 'distribution' more consistently

docs/installation.rst

@@ -7,7 +7,7 @@ Installation
 There are different ways to install |project_name|:
 
 - :ref:`distribution-package` - easy and fast if a package is
-  available from your distribution / for your operating system.
+  available from your distribution.
 - :ref:`pyinstaller-binary` - easy and fast, we provide a ready-to-use binary file
   that comes bundled with all dependencies.
 - :ref:`source-install`, either:
@@ -24,19 +24,19 @@ There are different ways to install |project_name|:
 Distribution Package
 --------------------
 
-Some Linux and BSD distributions might offer a ready-to-use ``borgbackup``
+Some distributions might offer a ready-to-use ``borgbackup``
 package which can be installed with the package manager.  As |project_name| is
 still a young project, such a package might be not available for your system
 yet.
 
-================ ===================== =======
-Operating system Source                Command
-================ ===================== =======
-Arch Linux       AUR_
-Debian           `unstable/sid`_       ``apt install borgbackup``
-Ubuntu           `Xenial Xerus 15.04`_ ``apt install borgbackup``
-OS X             `Brew cask`_          ``brew cask install borgbackup``
-================ ===================== =======
+============ ===================== =======
+Distribution Source                Command
+============ ===================== =======
+Arch Linux   AUR_
+Debian       `unstable/sid`_       ``apt install borgbackup``
+Ubuntu       `Xenial Xerus 15.04`_ ``apt install borgbackup``
+OS X         `Brew cask`_          ``brew cask install borgbackup``
+============ ===================== =======
 
 .. _AUR: https://aur.archlinux.org/packages/borgbackup/
 .. _unstable/sid: https://packages.debian.org/sid/borgbackup