doc: Sync "how to upgrade" with 0.20.0 release notes

Author: MarcoFalke

doc/release-notes.md

@@ -34,31 +34,27 @@ How to Upgrade
 ==============
 
 If you are running an older version, shut it down. Wait until it has completely
-shut down (which might take a few minutes for older versions), then run the
+shut down (which might take a few minutes in some cases), then run the
 installer (on Windows) or just copy over `/Applications/Bitcoin-Qt` (on Mac)
 or `bitcoind`/`bitcoin-qt` (on Linux).
 
 Upgrading directly from a version of Bitcoin Core that has reached its EOL is
-possible, but it might take some time if the datadir needs to be migrated. Old
+possible, but it might take some time if the data directory needs to be migrated. Old
 wallet versions of Bitcoin Core are generally supported.
 
 Compatibility
 ==============
 
-Bitcoin Core is supported and extensively tested on operating systems using
-the Linux kernel, macOS 10.12+, and Windows 7 and newer. It is not recommended
-to use Bitcoin Core on unsupported systems.
-
-Bitcoin Core should also work on most other Unix-like systems but is not
-as frequently tested on them.
+Bitcoin Core is supported and extensively tested on operating systems
+using the Linux kernel, macOS 10.12+, and Windows 7 and newer.  Bitcoin
+Core should also work on most other Unix-like systems but is not as
+frequently tested on them.  It is not recommended to use Bitcoin Core on
+unsupported systems.
 
 From Bitcoin Core 0.20.0 onwards, macOS versions earlier than 10.12 are no
 longer supported. Additionally, Bitcoin Core does not yet change appearance
 when macOS "dark mode" is activated.
 
-In addition to previously supported CPU platforms, this release's pre-compiled
-distribution provides binaries for the RISC-V platform.
-
 Notable changes
 ===============