Merge branch 'typos' into 'mkdocs'

typos, introduce centos8

See merge request linuxsupport/linuxtraining!1

docs/distributions/c8.md

 # CentOS 8
 
-Although not released yet officially at CERN, it will be soon the recommended release, so you can already test it. More details:
+## A bit of history
 
-<http://linux.web.cern.ch/linux/centos8/>
+CentOS 8 @ CERN was initially introduced via an [ASDF session](https://indico.cern.ch/event/866058/) on the 12.12.2019
+The operating system is supported by CERN IT as the next production linux distribution of CERN, as of April 2020. We strongly encourage all users of SLC6 and CC7 to migrate to C8.
 
-We will update this page in due time.
+> The CentOS Project is a community-driven free software effort focused on delivering a robust open source ecosystem around a Linux platform. Packages contained in CentOS are built from source code from the RedHat Enterprise Linux (RHEL) distribution. More information on the CentOS project can be found upstream at the [CentOS website](https://www.centos.org/).
+
+For more details on CentOS at Cern: <http://linux.web.cern.ch/linux/centos8/>
\ No newline at end of file

docs/distributions/supported.md

 # CERN Linux Distributions
 
-At CERN, two distributions are supported:
+At CERN, three distributions are supported:
 
+* CentOS 8
 * CERN CentOS 7
 * Scientific Linux CERN 6 (Support ending November 2020)
 
-And one is coming soon (Q2 2020):
-
-* CentOS 8
-
 Scientific Linux and CentOS are derived from Red Hat Enterprise Linux (RHEL), with Red Hat trademarks removed, thus making it freely available.
 Scientific Linux and CentOS deovelopers use Red Hat's source code to create a final product similar to RHEL.
 

docs/storage/s3.md

-# CVMFS
+# S3
 
 Official documentation: <http://cern.ch/cephdocs>